JPH0833838B2 - Computer system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a computer system including a micro CPU and a memory peripheral control LSI.

(Prior Art) In an electronic device that backs up stored contents with a battery, even if the power is turned off, all the states necessary for the program currently being executed are retained, and the program is continuously executed when the power is turned off again. Some have functions.
Here, this function is called the resume function (Resume),
The following description will be given. In order to realize this function, it is necessary to retain the contents of all registers used by the program being executed.

By the way, many of these conventional devices are realized by holding only the contents of the registers of the CPU. However, in this case, the state of the circuit controlling the peripheral input / output device connected to the CPU is not retained, and thus the complete resume function is not provided. In order to hold the control circuits of the peripheral input / output devices, it is necessary to hold the data indicating the control states of them as well as the CPU registers. The system configuration of this type of device is shown in FIG. 33,34 in the figure
Is an input / output controller (IOC), and is a commercially available L for input / output control
Composed of SI. These can be controlled by input / output commands issued from the CPU 31. The memory 32 receives power from a main power source (not shown) when the power source is N
It is a non-volatile memory that receives power from a backup power source such as a battery (not shown) during FF and can retain the stored data even during power FF. CPU31, I / O controller 33,3
The power of 4 receives the power from the main power supply only, and the power FF
Time is not backed up.

(Problems to be Solved by the Invention) By the way, recently, due to progress in semiconductor technology, microcomputers, memories, and peripheral control LSIs have been supplied at low cost. A relatively high-performance computer system can be constructed simply by combining these components appropriately. The control of the peripheral control LSI is performed by an input / output register accessible by an input / output (INPUT / OUTPUT) instruction from the CPU. Therefore, by holding the data in the I / O registers built into these peripheral control LSIs, the state of not only the CPU but also the I / O device can be held, and a more complete resume function (Resume function when power is turned on FF It is possible to realize the function of continuously executing the time program). However, many peripheral control LSs
I has a write-only input / output register. With such an I / O register, the CPU cannot read the contents of the I / O register (write-only) of the control LSI at power FF and save it in the memory, so the state of the LSI cannot be completely saved. It becomes impossible to hold.

The present invention has been made based on the above circumstances, and an object thereof is to provide a computer system that realizes a more complete resume function.

[Structure of Invention]

(Means for Solving Problems) The present invention provides a method for backing up (saving) an input / output register built in a peripheral control LSI on a non-volatile memory.
In addition to the read-only I / O registers and read / write I / O registers of the LSI, it is possible to back up the write-only I / O registers to realize a more complete resume function.

Therefore, when writing data to the write-only I / O register (CPU cannot read) of the peripheral control LSI, the same data is written to the copy register that is newly added when the power is turned on again. Is read and the program is continuously executed.

(Operation) In the above configuration, immediately before the power is turned off, the contents of the input / output registers built into the peripheral control LSI are saved together with all the registers of the CPU. At this time, the CPU reads the contents of each register and writes them to the non-volatile memory. Where CP
When U executes a read command to the write-only I / O register built in the peripheral control LSI, the data is read from the copy register. When the power is turned on again, all the data saved in the non-volatile memory is returned to the original state. As a result, the program interrupted due to the power-off request can be re-executed from that state. As a result, a complete resume function can be realized.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 11 is a microprocessor (μCPU) 12
Is a memory, 13 and 14 are peripheral control LSIs, and a computer system is constructed by commonly connecting these components to the input / output bus 15. In the present invention, an input / output register file 16 is further connected to this input / output bus 15. Among the input / output registers built in the peripheral control LSIs 13 and 14, there are write-only input / output registers. The externally connected input / output register file 16 is a circuit block provided to make a copy of these write-only input / output registers and enable the micro CPU 11 to read the data. Specifically, the microprocessor 11
When the CPU executes an output instruction to the write-only input / output register built in the peripheral control LSIs 13 and 14, the write data from the microprocessor 11 is simultaneously written to the write-only input / output register and the corresponding input / output register in the input / output register file 16. It is also written in the position. This I / O register file 16
Can be read as well as written.

FIG. 2 is a flow chart showing the operation of the embodiment of the present invention.

First, referring to the flowchart shown in FIG.
The operation of the embodiment shown in the figure will be described in detail. Power supply
Immediately before the FF, the contents of the input / output registers built in the peripheral control LSIs 13 and 14 are saved together with all the registers built in the microprocessor 11. At this time, the microprocessor 11 reads the contents of each register and writes them in the non-volatile memory. Normally, it is pushed to the stack position on the memory 12 indicated by the stack point of the microprocessor 11. If the microprocessor 11 executes an input command (read command) to the write-only input / output registers contained in the peripheral control LSIs 13 and 14, the data is not from the peripheral control LSIs 13 and 14, but the input / output register file.
It will be read from 16.

When the power is turned on (returned on), all the data saved in the nonvolatile memory 12 is returned to the original state. Now, the program suspended due to the power-off request can be re-executed from that state. Here, not only the microprocessor 11, but also the states of the peripheral input / output control circuits can be re-executed.

〔The invention's effect〕

As described above, according to the present invention, when the power is turned on again, the CPU
Peripheral control LSIs other than the above can be returned to the state immediately before the power was cut off, so that the program can be continuously executed, a complete resume function can be realized, and a complete resume function can be realized. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flow chart showing an operation of the embodiment of the present invention, and FIG. 3 is a block diagram showing an example of construction of a conventional computer system. 11 …… Microprocessor (μCPU), 12 …… Memory, 1
3,14 ... peripheral control LSI, 15 ... I / O bus, 16 ... I / O register file.

Claims (1)

[Claims] Claims: 1. Having a CPU, when a power-off request is made, the program currently being executed is interrupted, and when the power is turned on again, the data relating to the hardware state necessary for continuing execution of the program is non-volatile. It is a computer system that saves in storage means and is indispensable for continuous execution of the above program.
A register that holds data related to the hardware state that U cannot read, a copy register to which the same data is written when the above CPU writes data to the above register, and a copy instead of the above register when a power-off request is made. A saving means for reading the data from the register for saving data in the nonvolatile storage means, and a resetting means for reading the data from the nonvolatile storage means and resetting the data in the register when the power is turned on again. A computer system provided with.