JP3909080B2 - Data processor - Google Patents

Description

  The present invention relates to a semiconductor processor integrated data processor, and more particularly to a debugging support function in a data processor, for example, a technique effective when applied to traces for a plurality of types of internal buses built in the data processor.

  A data processor such as a microcomputer is equipped with other circuit modules together with a CPU. However, the number of built-in circuit modules has increased due to the demand for higher functionality, and the configuration of the internal bus has become complicated accordingly. When debugging a system using a data processor, it is necessary to monitor the internal state of the data processor while executing the target program, and use it for debugging. However, in situations where the data processor's circuit configuration and bus configuration are complicated It has been found by the present inventor that it becomes difficult to monitor internal information of various internal buses while executing a target program, and to monitor the bus information in real time or in a state close to this.

  As documents focusing on the internal data trace function in the data processor, there are JP-A-11-219303 and JP-A-3-90955 which describe a multiprocessor trace method. The former document does not consider the viewpoint of monitoring a plurality of buses and the viewpoint of adding processor identification information to trace information. The latter document exemplifies a viewpoint of using identification information indicating from which CPU the bus information is from.

JP 11-219303 A Japanese Patent Laid-Open No. 3-90955

  However, the latter document does not take into consideration the monitor for a plurality of buses. In short, no attention has been paid to the function of enabling monitoring of data of a plurality of buses in parallel and identifying the bus being monitored. Further, in the latter document, bus information and identification information are output in parallel from dedicated terminals, and assuming that the information is output from a one-chip data processor, it cannot be realized due to restrictions on the number of external terminals. It is expected that there may be cases.

  An object of the present invention is to provide a data processor having a debugging support function capable of monitoring a plurality of types of internal buses externally and identifying the buses being monitored.

  Another object of the present invention is to provide a data processor having a debugging support function capable of externally monitoring a plurality of types of internal buses in parallel.

  Another object of the present invention is to provide a data processor having a debugging support function capable of outputting information to be traced and identification information enabling identification of a route through which the information is transmitted from the same external terminal.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  [1] In the data processor according to the first aspect of the present invention, a CPU, a debug support module, and other circuit modules are mounted on a semiconductor chip. The debug support module selects an information transmission path according to a trace condition from a plurality of information transmission paths used for the operation of the CPU or other circuit modules, and trace information obtained according to the trace condition from the selected information transmission path At the same time, the attribute information of the information is held in the buffer circuit, and the trace information and the attribute information held in the buffer circuit can be serially output to the outside of the semiconductor chip in a predetermined format.

  The attribute information is identification information of an information transmission path, for example, a bus, through which corresponding trace information is transmitted. The attribute information is CPU identification information that makes it possible to identify which CPU of the multi CPU is based on the operation of causing the corresponding trace information to appear in the information transmission path.

  As described above, since it is possible to monitor the information to be traced and its attribute information outside the data processor, a plurality of types of internal buses can be monitored externally, and the bus being monitored can be identified. is there. In addition, since trace information and its attribute information are serially output to the outside, the information can be output from the same external terminal, reducing the situation where the debug support function cannot be implemented due to restrictions on the number of external terminals in the package can do.

  [2] As a specific aspect of the debug support function in the data processor, when read access is a trace condition, if the trace information is address information and data information for read access, the attribute information has an access type Information indicating read access, bus identification information indicating the type of information transmission path, and size information indicating the size of information to be traced may be used.

  When the trace information is address information and data information for write access when the write access is set as a trace condition, the attribute information includes information indicating that the access type is write access, and the type of information transmission path. The bus identification information to be displayed and the size information indicating the size of the information to be traced may be used.

  Further, when the branch of instruction execution by the CPU (for example, branch by execution of branch instruction by CPU, interruption or exception processing) is set as a trace condition, if the trace information is branch source address information and branch destination address information, The attribute information may be information indicating that a branch is traced, information indicating the size of branch source address information to be traced, and information indicating the size of branch destination address information to be traced.

  When the branch of instruction execution by the CPU is set as a trace condition, if the trace information is branch source address information, the attribute information indicates information indicating that the branch is traced and the size of the branch source address information to be traced. It may be information. Similarly, if the trace information is branch destination address information at that time, the attribute information may be information indicating that the trace is at the time of branching and information indicating the size of the branch destination address information to be traced.

  [3] In the data processor according to the second aspect of the present invention, a CPU, a debug support module, and other circuit modules are mounted on a semiconductor chip. The debug support module selects an information transmission path according to a trace condition from a plurality of information transmission paths used for the operation of the CPU or other circuit modules, and acquires trace information from the selected information transmission path according to the trace condition. A selection circuit that holds the attribute information of the information together with the trace information selected by the selection circuit, and the trace information and the attribute information held in the buffer circuit in a predetermined format. The operation of the selection circuit, the buffer circuit, and the output circuit is controlled based on an output circuit that enables serial output to the outside, a trace condition specified by the CPU, and an operation state by the CPU and other circuit modules. And a control circuit.

  Even in a data processor according to this point of view, it is possible to monitor a pair of trace information and its attribute information externally, so it is possible to monitor a plurality of types of internal buses externally and identify the buses being monitored. In addition, information to be traced and its attribute information can be output from the same external terminal.

  [4] If the buffer circuit in the data processor according to the second aspect is a FIFO buffer circuit, it is not necessary to consider the address space of the CPU for information storage. At this time, the control circuit may output an information code indicating that the information to be traced is lost without being held in the buffer circuit due to the full state of the FIFO buffer circuit from the output circuit to the outside of the semiconductor chip. As a result, it is possible to easily grasp the lack of information to be traced outside. In order to suppress the lack of information to be traced, the control circuit may give an instruction to temporarily stop a new bus access operation in units of bus cycles in response to the full state of the FIFO buffer circuit. In short, bus access by the CPU or DMAC may be stalled until the storage area is free in the FIFO buffer circuit.

  [5] In the selection circuit in the data processor according to the second aspect, for example, an information transmission path for obtaining trace information is selected from a plurality of information transmission paths, and information on the selected information transmission path is stored in bus cycle units. A first selector that holds information, a second selector that selects information transmission paths for obtaining trace information from a plurality of information transmission paths, and holds information on the selected information transmission paths in units of bus cycles, and a current execution An instruction address buffer for holding the instruction address of the instruction immediately before the instruction address therein, and a third selector for selecting one from the outputs of the first selector, the second selector, and the instruction address buffer and giving it to the buffer circuit The structure which has is adopted. At this time, the control circuit causes the first and second selectors to select the information transmission path specified by the trace condition, and the third selector selects the first selector according to the appearance of the access mode specified by the trace condition. The output of the second selector or the instruction address buffer is selected.

  As a result, the states of the plurality of internal buses selected by the first selector and the second selector can be monitored in parallel.

  In order to cope with the case where the access mode to be traced appears in the same bus cycle on a plurality of buses that can be monitored in parallel, the control circuit transmits each information selected by the first selector and the second selector. When the access mode specified by the trace condition in the path appears in the same bus cycle, a new bus access operation by the CPU or DMAC is temporarily stopped, and appears in both information transfer paths in the respective access modes. The information held in the second selector may be stored in the buffer circuit serially via the third selector.

  [6] As a more specific mode in the data processor of the second aspect, the other circuit module includes a DSP, an X memory, a Y memory, a DMAC, and a bus state controller, and an address and data are respectively transmitted as the information transmission path. When having an I bus, an X bus, a Y bus, and a D bus for transmitting, and an IC bus and a DC bus for transmitting bus access control information, the CPU can output addresses to the I bus, the X bus, and the Y bus, Data can be input / output via the I bus, and bus access control information can be output to the IC bus. The DSP can input / output data via the I bus, X bus, and Y bus, and the IC bus and DC Bus access control information can be input via a bus, and the X memory can input addresses from the I bus, X bus, and D bus. Data input / output is possible between the I bus, X bus and D bus, and the Y memory can be addressed from the I bus, Y bus and D bus, and the I bus, Y bus and D bus. Data input / output can be input to the bus, bus access control information can be input via the IC bus and DC bus, and the DMAC can set transfer control conditions via the I bus, and the D bus The bus state controller can output bus access control information to the DC bus for access control by the DMAC.

  At this time, the control circuit is connected to the IC bus and the DC bus, and determines the occurrence of an access operation that matches a trace condition based on access control information supplied via the IC bus and the DC bus, The selection circuit may select the bus used for the access operation that matches the trace condition.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, since information to be traced and its attribute information can be monitored outside the data processor, information transmission paths such as a plurality of types of internal buses can be monitored externally and monitored respectively. An information transmission path can be identified. In addition, since trace information and its attribute information are serially output to the outside, the information can be output from the same external terminal, reducing the situation where the debug support function cannot be implemented due to restrictions on the number of external terminals in the package can do.

  In addition, if a plurality of information transmission paths are selected from a plurality of information transmission paths according to the trace conditions, and trace information is acquired from the selected information transmission paths according to the trace conditions, a plurality of types of information transmission paths can be parallelized. Can be monitored externally.

<Data processor>
FIG. 1 shows an example of a data processor according to the present invention. The data processor 1 shown in the figure is formed on a single semiconductor chip or a semiconductor substrate such as single crystal silicon by, for example, a CMOS integrated circuit manufacturing technique, and is not particularly limited, but a reduced instruction set (for example, 16) as a RISC processor. A CPU (central processing unit) 2 to which a bit fixed length instruction set) is applied, and a DSP 3 capable of executing a product-sum operation at high speed by executing operations and data load / store in parallel. Further, data memories (XMEM, YMEM) 4 and 5 constituted by SRAM, bus state controller (BSC) 6, input / output circuit (I / O) 7 such as IO port, DMAC (direct memory access controller) 8. A debug support module (AUD) 9 is provided. Although not particularly limited, the CPU 2 can execute an instruction by pipeline processing, and apparently can execute one instruction for each cycle of the operation reference clock signal of the CPU 2.

  The internal bus of the data processor 1 is roughly divided into a plurality of types for each function, and an I bus (CPU address bus IAB, CPU data bus IDB) and an X bus (XMEM address bus XAB, XMEM data bus XDB), Y bus (YMEM address bus YAB, YMEM data bus YDB) and D bus (DMA address bus DAB, DMA data bus DDB), and IC bus (CPU command bus ICMDB) for transmitting bus access control information And a DC bus (DMA command bus DCMDB).

  The CPU 2 decodes the fetched instruction by an instruction decoder (not shown), and calculates address information and data information using a general-purpose register and an arithmetic logic unit (not shown) according to the decoding result. The CPU 2 can output addresses to the address buses IAB, XAB, and YAB, can input / output data via the data bus IDB, and can output bus access control information (bus command) to the command bus ICMDB. The bus command includes information for specifying read / write distinction, data access / instruction fetch distinction, data size, and the like.

  The DSP 3 has a decoder, a multiplier, an arithmetic logic unit (ALU), a data sum file dedicated to product-sum operations, and the like that decode DSP instructions (not shown). Although not particularly limited, the CPU 2 performs access control of data necessary for the operation of the DSP 3. The DSP 3 inputs the data read from the data memories (XMEM, YMEM) 4 and 5 by the access control of the CPU 2 and performs digital signal processing calculation. The calculation result data output from the DSP 3 is stored in the memory (by the CPU 2 access control). (XMEM, YMEM) 4, 5 etc. In short, the DSP 3 can input and output data via the data buses IDB, XDB, and YDB, and can input bus access control information (bus commands) via the command buses ICMDB and DCMDB.

  The XMEM 4 and YMEM 5 are constituted by SRAM or DRAM, and are used as a data memory of the DSP 3 or a work memory of the CPU 2. The XMEM 4 can input addresses from the address buses IAB, XAB, and DAB, and can input and output data to and from the data buses IDB, XDB, and DDB. The bus access control information (command bus ICMDB and DCMDB) Bus command). The YMEM 5 can input addresses from the address buses IAB, YAB, and DAB, can input / output data to / from the data buses IDB, YDB, and DDB, and can access bus access control information (via the command buses ICMDB and DCMDB). Bus command).

  The DMAC 8 can set transfer control conditions from the CPU 21 via the address bus IAB and the data bus IDB, outputs an address to the address bus DAB, uses the data bus DDB, or inside the data processor 1 or Data transfer control is performed between the inside and outside of the data processor 1.

  In response to the access operation of the CPU 2 or the data transfer control by the DMAC 8, the BSC 6 activates a necessary bus cycle for external bus access to the external bus 11 and peripheral circuit access (not shown) via the peripheral bus 10. Control. When the data transfer destination or transfer source by the DMAC 8 is a circuit module inside the data processor 1, the bus command required by the internal circuit module is output from the BSC 6 to the command bus DCMDB in response to the DMA request from the DMAC 8.

  The debug support module 9 includes a selection circuit 20, a FIFO buffer circuit 21, an output circuit 22, and a control unit 23 and a control register unit 24 that constitute a control circuit. The selection circuit 20 is connected to the I bus (IAB, IDB), the X bus (XAB, XDB), the Y bus (YAB, YDB), and the D bus (DAB, DDB), and is a bus designated by a trace condition. When an access mode indicated by the trace condition appears on the selected bus, information on the bus related to the access mode is selected. A plurality of buses can be specified in parallel according to the trace condition. The FIFO buffer circuit 21 holds the attribute information of the information together with the information (trace information) selected by the selection circuit 20. The attribute information is, for example, identification information of the bus to which the trace information is transmitted. The output circuit 22 enables the trace information held in the FIFO buffer circuit 21 and its attribute information to be output in series outside the data processor 1 as packet data of a predetermined format. Although not particularly limited, the serial output data AUDATA is data in units of 4 bits. In the control register unit 24, trace conditions are set by the CPU 2 via the I bus (IAB, IDB). The control unit 23 monitors the operation state of the circuit module such as the CPU 2 via the command buses ICMDB and DMDB, and the selection circuit 20 is based on the trace condition set in the control register unit 24 and the monitored operation state. The operation of the FIFO buffer circuit 21 and the output circuit 22 is controlled. The control unit 23 outputs a clock signal AUDCK to which the output of the data AUDDATA in units of 4 bits is synchronized and a synchronization signal AUDSYNC for each packet to the outside of the data processor 1.

  The debug support module 9 is enabled by setting a debug mode in the data processor 1, for example. Such a debug mode may be set when the data processor 1 is connected to the target system to be debugged and the data processor 1 executes the target program. When the data processor 1 is executing the target program, the emulator connected to the outside of the data processor 1 can monitor the trace information output from the debug support module 9 and its attribute information. As described above, by the action of the debug support module 9, a plurality of types of internal buses (I bus, X bus, Y bus, D bus) of the data processor 1 can be monitored externally, and the type of bus being monitored Can also be identified. In addition, since the trace information and its attribute information are serially output to the outside, the information can be output from the same external terminal of the data processor 1, and the debug support function cannot be implemented due to restrictions on the number of external terminals of the package. Can be reduced.

  FIG. 2 shows another example of a data processor. The data processor 1A shown in the figure has a multi-CPU configuration as compared to FIG. That is, it has a second CPU 12, and the CPU 12 is connected to the BSC 6 via a CPU address bus I2AB, a CPU data bus I2DB, and a CPU command bus I2CMDB. At this time, buses I2AB and I2DB are also connected to the selection circuit 20, and input information from the buses I2AB and I2DB can be monitored. As attribute information in this configuration, it is desirable to further include CPU identification information that makes it possible to identify which of the CPUs of the multiple CPUs 2 and 12 the operation of causing the trace information to appear on the bus is based on. The control unit 23 also monitors the appearance of the access mode on the buses I2AB and I2DB specified by the trace condition by inputting information on the command bus I2CMDB. Other configurations are the same as those in FIG. 1, and the same operations and effects as described above are obtained even in a multi-CPU configuration.

<Packet data format>
FIG. 3 illustrates a format of the packet data output from the output circuit 22 of FIG. The packet data has attribute information expressed by CMD1, CMD1E, and CMD2, and trace information following the attribute information. CMD1 is 4-bit code data indicating the type of access. In this example, the type of access that is a trace condition is roughly divided into a branch trace (BPC), a read access (WDRM), and a write (store) access (WDWM) when the branch of instruction execution by the CPU 2 is used as the trace condition. And a unique code is assigned to each. When branch trace is used as a trace condition, the trace information is branch source address information and / or branch destination address information. When read access or / and write access is used as a trace condition, the trace information is access address information and access data. Here, the branch trace is intended for a branch caused by execution of a branch instruction by the CPU 2. It is also possible to target a branch due to the occurrence of an interrupt or exception.

  CMD1E is a 4-bit code indicating the type of bus. In the case of the branch trace, the address information of the branch destination / branch source to be traced is only acquired via the address bus IAB, so the code CMD1E is omitted. In the case of read access and / or write access, 1-bit processor identification information pt and 3-bit bus identification information bt are included. The bus identification information bt indicates I bus trace, Y bus trace, X bus trace, both X and Y bus trace, and D bus trace according to the value.

  CMD2 is a 4-bit code indicating the information size. When following the branch trace (BCP) code, sda indicates the size of the branch destination address with 2 bits, and ssa indicates the size of the branch source address with 2 bits. Since the address information is output after being subjected to compression processing described later, the lower 4 bits output, the lower 8 bits output, the lower 16 bits output, and the 32-bit full address of the address information according to the value of sda / ssa Indicates the output. When following a store access (WDWM) code or a read access (WDRM) code, sa indicates the size of the source address with 2 bits, and sd indicates the data size with 2 bits. Since the address information is output after compression processing described later, according to the value of sa, lower 4 bits output and lower 8 bits output of the address information (when both X and Y bus traces are instructed by bt) , X and Y respectively lower 4 bits output), lower 16 bits output (when both traces X and Y are instructed by bt, lower 8 bits are output X and Y respectively), 32 bits full address output . The data size indicates 8 bits, 16 bits, or 32 bits according to the value of sd (when both the X and Y bus traces are indicated by bt, 16 bits are output for each of X and Y).

  The code data CMD1 is assigned a code indicating a standby state (STDBY) and a data lost state (LOST) in addition to the branch trace (BPC), read access (WDRM), and write access (WDWM). The STDBY code indicates that the debug support module 9 is in the standby state, meaning that there is no subsequent data. The LOST code indicates that information to be traced is lost without being held in the FIFO buffer circuit 21 due to the full state of the FIFO buffer circuit 21. As a result, it is possible to easily grasp the lack of information to be traced outside. In order to suppress the loss of information to be traced, the control unit 23 gives an instruction to temporarily stop a new bus access by the CPU 2 or the DMAC 8 in response to the full state of the FIFO buffer circuit 21. do it. In short, the bus access by the CPU 2 or the DMAC 8 may be stalled until the storage area of the FIFO buffer circuit 21 becomes free.

<< AUD control register >>
FIG. 4 shows a detailed example of the debug support module 9 of FIG. The control unit 23 includes an input bus control unit 30, a FIFO control unit 31, an output control unit 32, and a bus stall control unit 33. The output circuit 22 includes an address data compression unit 35, a packet conversion unit 36, an attribute information generation unit 37, and a demultiplexer 38. The control register unit 24 includes control registers 39A and 39B and an address decoder 40.

  The control registers 39A and 39B are each composed of a 16-bit register as illustrated in FIG. 5 and are arranged in the address space of the CPU 2, and the address is supplied to the address decoder 40 from the address bus IAB. Read / write is enabled via the bus IDB. The significance of each bit of the control registers 39A and 39B is illustrated in FIGS.

  As illustrated in FIG. 6, the branch trace function bits BRE and BR are output according to the set values of the branch trace disabled, the branch trace enabled, the branch source and destination addresses output, the branch trace enabled, the branch source address output only, the branch The trace is valid and only the branch destination address is output.

  Further, two types of trace conditions other than the branch trace can be specified simultaneously (window A data trace, window B data trace), and one information trace (window A data trace) is a window data trace function bit of FIG. It is determined by designation by WA1 and WA0 and designation by trace bus select function bits WA0B2, WA0B1 and WA0B0 for each window in FIG. According to the values of the former function bits WA1 and WA0, the window A data trace function is invalid, only the window A data trace write access is valid, only the window A data trace read access is valid, and the window A data trace write and read access are valid. Instruct. The function bits WA0B2, WA0B1, and WA0B0 designate one of the I bus, X bus, Y bus, and D bus as the window A data trace target bus according to the value. The other information trace (window B data trace) is determined by designation by window data trace function bits WB1 and WB0 in FIG. 6 and designation by trace bus select bits WB0B2, WB0B1 and WB0B0 for each window B in FIG. According to the values of the former function bits WB1 and WB0, the window B data trace function is invalid, only the window B data trace write access is valid, only the window B data trace read access is valid, and the window B data trace write and read access are valid. Instruct. Function bits WB0B2, WB0B1, and WB0B0 specify one of the I, X, Y, and D buses as the window B data trace target bus according to the value.

  The processor core select bit PT0 is fixed at a value of 1 because there is only one CPU in FIG. In the example of FIG. 2, the CPU 12 may be designated by PT0 = 0 and the CPU2 may be designated by PT0 = 1. Alternatively, CPU2 may be designated by PT0 = 0, and CPU2 and CPU12 may be designated by PT0 = 1.

  The trace mode bit TM shown in FIG. 6 designates the full trace mode or the real-time trace mode depending on its value. In the full trace mode, all trace information is output. When the FIFO buffer circuit 21 becomes full, the bus stall control unit 33 stalls the CPU 2 until the FIFO buffer circuit 21 becomes full. The real-time trace mode is a mode for outputting trace information in real time without stopping the CPU 2. When the FIFO buffer circuit 21 becomes full or trace information is generated in parallel in the windows A and B, the attribute is set. The information generation unit 37 issues the LOST code.

<Selection circuit>
FIG. 8 shows an example of the selection circuit. The selection circuit 20 shown in the figure includes a first selector (window A selector) 41, a second selector (window B selector) 42, a third selector 43, and an instruction address buffer 44. The first selector 41 selects a bus for obtaining information to be traced from the I bus (IAB, IDB), the X bus (XAB, XDB), the Y bus (YAB, YDB), and the D bus (DAB, DDB). Information on the selected bus is selected and held in units of bus cycles. Similarly, the second selector 42 obtains information to be traced from the I bus (IAB, IDB), X bus (XAB, XDB), Y bus (YAB, YDB), and D bus (DAB, DDB). A bus is selected and information on the selected bus is held in units of bus cycles. The instruction address buffer 44 holds the instruction address of the instruction immediately before the instruction address currently being executed by the CPU 2. In short, the instruction address buffer 44 receives an instruction address transmitted to the address bus IAB of the I bus, and holds it for a predetermined period after the next instruction address is input until the execution of the next instruction is completed. The third selector 43 selects one of the outputs from the first selector 41, the second selector 42, and the instruction address buffer 44 and supplies the selected one to the FIFO buffer circuit 21.

  At this time, the input bus control unit 30 provides the first selector 41 with a bus selection signal 45A specified by the trace bus select bits WA0B2, WA0B1, and WA0B0 for each processor core for the window A of the control register 39B. Similarly, the input bus control unit 30 provides the second selector 42 with a bus selection signal 45B designated by the trace bus select bits WB0B2, WB0B1, and WB0B0 for the window B for the processor B in the control register 39B. In response to the appearance of the access mode specified by the branch trace function bits BRE and BR and the window data trace function bits WA1, WA0, WB1 and WB0 of the control register 39A, the input bus control unit 30 for the third selector 43 The output of the first selector 41, the second selector 42 or the instruction address buffer 44 is selected and a selection signal 46 is output. Whether or not the access mode specified as the trace condition has appeared may be determined by monitoring the states of the command buses ICMDB and DCMDB. For example, when the access mode specified by the trace condition appears on the bus selected by the first selector 41, the input bus control unit 30 causes the third selector 43 to select the output of the first selector 41. When the access mode specified by the trace condition appears on the bus selected by the second selector 42, the input bus control unit 30 causes the third selector 43 to select the output of the second selector 42. Further, when the input bus control unit 30 detects execution of a branch instruction when the branch trace is instructed effectively, the next instruction address as the branch destination instruction is input to the first selector 41 from the address bus IAB. Thereafter, the third selector 43 is caused to supply the branch source address held in the instruction address buffer 44 and the branch destination address held in the first selector 41 to the FIFO buffer circuit 21.

  The selection circuit 20 can monitor the states of the internal buses selected by the first selector 41 and the second selector 42 in parallel. At this time, an access mode to be traced on a plurality of buses that can be monitored in parallel may appear in the same bus cycle. In the state where the full trace mode is specified, the input bus control circuit 30 causes the access mode specified by the trace condition to appear in the same bus cycle in each bus selected by the first selector 41 and the second selector 42. In this case, the bus stall control unit 33 temporarily stops the instruction execution by the CPU 2 or the data transfer operation by the DMAC, and appears in both buses in the respective access modes, and the traces held in the first and second selectors 41 and 42. Information is stored in the FIFO buffer circuit 21 serially via the third selector 43.

<Bus stall control>
Here, the bus stall control will be described in detail with reference to FIG. The input bus control unit 30 determines whether or not a state that matches the trace condition appears based on the bus commands from the command buses ICMDB and DCMDB, and determines the occurrence of the state that matches the trace condition as a hit signal HITa, HITb, HITi. Output as. The hit signal HITa is activated when it matches the window A data trace condition (when the trace data is acquired via the first and third selectors 41 and 43), and the hit signal HITb matches the window B data trace condition. (When trace data is acquired via the second and third selectors 42 and 43), the hit signal HITi is activated when a branch occurs in the instruction execution by the CPU 2. When the hit signals HITa, HITb, and HITi are activated, the input bus control unit 30 issues a write request to the FIFO control unit 31 by the signal 53.

  The FIFO control unit 31 controls reading / writing of data with respect to the FIFO buffer circuit 21 in a first-in first-out format. The full signal 50 is activated when there is no writable storage area, and the empty signal 51 is activated when there is no more readable data. A read request to the FIFI control circuit 31 is given by a signal 52.

  The bus stall control unit 33 receives the hit signals HITa, HITb, HITi, the full signal 50, and the setting data of the control registers 39A and 39B. When the full trace mode is instructed by the trace mode bit (TM) and the hit signals HITa, HITb, HITi are activated in the full state, the bus stall control unit 33 is ready for the I bus. The signal AUDIRDY or the bus ready signal AUDDRDY for the D bus is deactivated. According to this example, the bus ready signals AUDIRDY and AUDDRDY are supplied to the BSC 6, the bus access using the I bus is inhibited by deactivating the bus ready signal AUDIRDY, and the bus D is deactivated by deactivating the bus ready signal AUDDRDY. Bus access to be used is suppressed.

<< LOST flag control >>
Although not specifically shown, the bus stall control unit 33, when the real-time trace mode is instructed by the trace mode bit (TM), when the FIFO buffer circuit 21 is full, the hit signals HITa, HITb, HITi Each time it is activated, the LOST flag in the input bus control unit 30 is sequentially held in a set state. Thereafter, when the first empty space is generated in the FIFO buffer circuit 21, the input bus control unit 30 writes and controls the information on the number of sets of the LOST flag to the FIFO buffer circuit 21 via the FIFO control unit 31.

<Output control>
Here, the output control by the output circuit 22 will be described in detail with reference to FIG. The input bus control unit 30 decodes the contents of the bus command input from the command buses ICMDB and DCMDB, acquires bus access control information used as attribute information for each bus cycle, and provides the same to the FIFO buffer circuit 21. The FIFO buffer circuit 21 stores corresponding bus access control information together with address information and data information to be traced, for example, in the same FIFO storage stage. An instruction to write to the FIFO buffer circuit 21 is given by the signal 53. Reading to the FIFO buffer circuit 21 is instructed by a signal 52.

  The attribute information generation unit 37 receives the bus access control information read from the FIFO buffer circuit 21 and follows the control of the output control unit 32 that receives the set values of the control registers 39A and 39B, CMD1 and CMD1E described in FIG. , Attribute information is generated in the form represented by CMD2. The address data compression unit 35 compresses and outputs the address information as information to be traced read from the FIFO buffer circuit 21.

  The address information is compressed by a method of outputting a difference from the immediately preceding address information as illustrated in FIG. That is, as illustrated in FIGS. 9A and 9B, when all bits match or when there is a mismatch within the lower 4 bits, only the lower 4 bits of the current address information are output. To do. If there is a mismatch bit in the range from the 5th bit to the 8th bit as in (C), only the lower 8 bits of the current address information are output. If there is a mismatch bit in the range from the 9th bit to the 16th bit as in (D), only the lower 16 bits of the current address information are output. If there is a mismatch bit in the 17th to 32nd bits as shown in (E), the current address information is output as a full address. The packet conversion unit 36 performs format conversion of address information and data information according to the packet data format described with reference to FIG.

  The output control unit 32 selects the attribute information expressed by the CMD1, CMD1E, and CMD2 and the trace information output from the packet conversion unit 36 in a predetermined order by the demultiplexer 39 in synchronization with the clock signal AUDCK. The monitor data AUDDATA is output to the outside, and the packet synchronization signal AUDSYNC is changed for each packet.

  10 and 11 show output examples of data AUDATA, clock signal AUDCK, and packet synchronization signal AUDSYNC at the time of branch trace (BPC). In FIG. 10, after MD2, branch destination address information is 16 bits as DA and branch source address information is 8 bits as SA. In FIG. 11, the branch source address information is followed by 8 bits as SA after MD2.

  FIG. 12 shows an output example of data AUDATA, clock signal AUDCK, and packet synchronization signal AUDSYNC at the time of write access (WDWM). MD2 is followed by 16 bits of address information as A and 16 bits of data information as D.

  FIG. 13 shows an output example of the data AUDATA, the clock signal AUDCK, and the packet synchronization signal AUDSYNC when the windows A and B are continuously traced during write access (WDWM). In the two output operations before and after, MD2 is followed by 16 bits of address information as A and 16 bits of data information as D.

  FIG. 14 shows an output example of the data AUDATA, the clock signal AUDCK, and the packet synchronization signal AUDSYNC when the trace data is lost in the real-time trace. When data is lost, the LOST code is output, the packet synchronization signal AUDSYCK is set to low level by the output of the LOST code, and the packet synchronization signal AUDSYCK is already set to low level when the next BPC code is output. ing. The packet output after the LOST state can be distinguished from other packet outputs by the packet synchronization signal AUDSYCK. The attribute information generator 37 generates the LOST code based on the information on the number of sets of the LOST flag stored in the FIFO buffer circuit 21.

<< Connection between bus and FIFO buffer circuit >>
FIG. 15 schematically illustrates a connection form of the I bus and the FIFO buffer circuit by the selection circuit 20. The buses IAB and IDB each have 32 bits. One storage stage of the FIFO buffer circuit 21 is 74 bits here, and a 32-bit address storage area E1, a 32-bit data storage area E2, and a 10-bit attribute information area E3 are allocated.

  FIG. 16 schematically illustrates the connection form of the X bus, the Y bus, and the FIFO buffer circuit by the selection circuit 20. The number of bits of the X bus and Y bus is less than half that of the I bus. Although not particularly limited, the address buses XAB and YAB each have 15 bits, and XDB and YDB each have 16 bits. One storage stage of the FIFO buffer circuit 21 is 74 bits, and a 32-bit address storage area E1, a 32-bit data storage area E2, and a 10-bit attribute information area E3 are allocated as in FIG. Yes. However, two types of address buses XAB and YAB are connected in parallel to the upper and lower storage areas in the address area E1, and two types of data buses XDB and YDB are connected to the upper and lower storage areas in the data area E2. Connected in parallel. Therefore, when the X bus (XAB, XDB) and the Y bus (YAB, YDB) are to be traced, and an access state that matches the trace condition appears in parallel on both buses, both trace information is stored in the FIFI buffer at a time. It can be stored in the circuit 21. Therefore, in this case, trace information is not lost in the real-time trace mode, and no bus stall occurs in the full trace mode.

<< Trace information from other than bus >>
In the above description, the trace information is described as being acquired from the address bus and the data bus. FIG. 17 schematically illustrates the configuration of the data processor 1B that enables acquisition of trace information from other than the bus. For example, signal lines 62 and 63 to which signals to be traced such as internal states are transmitted from other circuit modules 60 and 61 such as a timer and a serial interface are connected to the selection circuit. A signal that defines generation of a signal to be traced (trace event), such as an interrupt signal, is input from the signal lines 64 and 65 to the control unit 23. Thereby, in response to occurrence of a desired trace event other than bus access, the corresponding event occurrence information can be stored as trace information in the FIFO buffer circuit. Also in this case, as described above, a plurality of buses and trace events can be monitored in parallel to acquire trace information, and these can be output to the outside in series as data AUDATA from a small number of external terminals.

  Although the invention made by the present inventor has been specifically described based on the embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the gist thereof.

  For example, other circuit modules are not limited to DSPs and memories, and can be changed as appropriate. The configuration of the bus as the information transmission path is not limited to the I bus, X bus, Y bus, and D bus, and can be changed as appropriate according to the type of the built-in circuit module. Further, the format of the packet for outputting the trace information, the type of code data, the significance of the set value of the control register, and the like can be appropriately changed. Although the configuration of FIG. 8 enables tracing by specifying two types of buses in parallel, a configuration in which three or more types of buses are specified in parallel may be adopted. Further, the address information as the trace information may be always output as a full address without performing any compression processing.

It is a block diagram which shows the 1st example of the data processor which concerns on this invention. It is a block diagram which shows what has multiple CPU as a 2nd example of the data processor which concerns on this invention. It is explanatory drawing for demonstrating the format of the said packet data output from the output circuit of FIG. It is a block diagram which shows a detailed example of the debug assistance module incorporated in the data processor of FIG. It is explanatory drawing which illustrates the control bit structure of a control register. It is explanatory drawing which shows the definition of the control bit of a control register. It is explanatory drawing which shows the definition of the control bit of a control register. FIG. 5 is a block diagram illustrating details of a selection circuit included in the debug support module of FIG. 4. It is explanatory drawing which illustrates the compression processing method of address information. 7 is a timing chart showing a first output example of data AUDATA, a clock signal AUDCK, and a packet synchronization signal AUDSYNC during branch trace (BPC). 12 is a timing chart showing a second output example of data AUDATA, clock signal AUDCK, and packet synchronization signal AUDSYNC at the time of branch trace (BPC). 6 is a timing chart showing an output example of data AUDATA, a clock signal AUDCK, and a packet synchronization signal AUDSYNC during a write access (WDWM). 10 is a timing chart showing an output example of data AUDATA, a clock signal AUDCK, and a packet synchronization signal AUDSYNC during continuous tracing of windows A and B during write access (WDWM). 10 is a timing chart showing an output example of data AUDATA, a clock signal AUDCK, and a packet synchronization signal AUDSYNC when trace data is lost in a real-time trace. It is a block diagram which illustrates typically the connection form of I bus and FIFO buffer circuit by a selection circuit. It is a block diagram which illustrates typically the connection form of X bus, Y bus, and FIFO buffer circuit by a selection circuit. It is a schematic block diagram which illustrates the data processor which enables acquisition of trace information from other than a bus.

Explanation of symbols

1 Data processor 2 CPU
3 DSP
4 X data memory (XMEM)
5 Y data memory (YMEM)
6 Bus state controller (BSC)
8 DMAC
9 Debugging support module (AUD)
IAB, IDB I bus XAB, XDB X bus YAB, YDB Y bus DAB, DDB D bus DCMDB DC bus ICMDB IC bus 20 selection circuit 21 FIFO buffer circuit 22 output circuit 23 control unit 24 control register unit 30 input bus control unit 31 FIFOI Control unit 32 Output control unit 33 Bus stall control unit 41 First selector 42 Second selector 43 Third selector 44 Instruction address buffer 50 Full signal 51 Empty signal 52 Read request signal 53 Write request signal AUDDATA packet data AUDCK clock signal AUDSYNC Packet synchronization Signal AUDDIRDY I-bus ready signal AUDDYDY D-bus ready signal

Claims (12)

A first central processing unit;
A second central processing unit;
A debug module;
A first bus connected to the first central processing unit and a debug module;
A second bus connected to the second central processing unit and a debug module;
A data processor formed on a semiconductor chip having a plurality of external terminals connected to the debug module,
The debug module includes trace information fetched from the first or second bus;
It has a buffer circuit that holds attribute information of trace information according to the trace condition,
The attribute information, see contains identification information indicating that the a trace information based on the execution operation by the first central processing unit or the second central processing unit,
The debug module can output an information code to the outside of the semiconductor chip via the external terminal,
The data processor is characterized in that trace information is not held in the buffer circuit because the buffer circuit is full . A first central processing unit;
A second central processing unit;
A debug module;
A first bus connected to the first central processing unit and a debug module;
A second bus connected to the second central processing unit and a debug module;
A data processor formed on a semiconductor chip having a plurality of external terminals connected to the debug module,
The debug module includes trace information fetched from the first or second bus;
It has a buffer circuit that holds attribute information of trace information according to the trace condition,
The attribute information includes identification information indicating trace information based on an operation executed by the first central processing unit or the second central processing unit,
The debug module is capable of outputting a data missing code indicating that trace information and attribute information have not been stored in the buffer circuit to the outside of the semiconductor chip via the external terminal. Processor. A first central processing unit;
A second central processing unit;
A debug module;
A first bus connected to the first central processing unit and a debug module;
A second bus connected to the second central processing unit and a debug module;
A data processor formed on a semiconductor chip having a plurality of external terminals connected to the debug module,
The debug module includes trace information fetched from the first or second bus;
It has a buffer circuit that holds attribute information of trace information according to the trace condition,
The attribute information includes identification information indicating trace information based on an operation executed by the first central processing unit or the second central processing unit,
The data processor , wherein the attribute information includes bus identification information indicating whether the bus from which the trace information is acquired is the first bus or the second bus . The data processor according to claim 2 , wherein the debug module performs control to temporarily stop the operation of the first or second central processing unit according to the output of the data missing code . 4. The data according to claim 3 , wherein the debug module is capable of outputting a data missing code indicating that trace information and attribute information have not been stored in the buffer circuit to the outside of the semiconductor chip via the external terminal. Processor. The debug module includes a selection circuit that selects the first bus or the second bus according to the trace condition;
It said debug module, any one data processor according to claim 1 to 3 for storing the trace information bus which is selected by the selection circuit in the buffer circuit. The debug module further includes a control register in which the trace condition is set by the first central processing unit,
The data processor according to claim 6 , wherein the selection circuit selects a bus according to a trace condition set in the control register . The data processor according to claim 6 , wherein the debug module outputs the trace information and the attribute information in a predetermined format to the outside of the semiconductor chip via the plurality of external terminals . The data processor according to claim 8 , wherein the debug module includes a control register indicating which of the first central processing unit and the second central processing unit is a trace . When the trace condition is read access,
The trace information includes read access address information and data information,
The data processor according to claim 8 , wherein the attribute information includes information indicating that an access type is read access, size information indicating a size of information to be traced, and the bus identification information . When the trace condition is write access,
The trace information includes write access address information and data information,
9. The data processor according to claim 8 , wherein the attribute information includes information indicating that an access type is write access, size information indicating a size of information to be traced, and the bus identification information . When the branch instruction is executed in the central processing unit is a trace condition, the trace information includes branch source address information, branch destination address information, information indicating the time when the branch occurred, and the size of the branch source address information. the attribute information and the data processor including請 Motomeko 8 wherein the including the information indicating information and the branch destination address information size indicating a.

Images