JPS5845049B2 - Data transfer reading method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data transfer reading method, and more particularly to a data transfer reading method capable of detecting data errors during data transfer between a keyboard and a keyboard control unit.

Conventionally, a parity method in which a parity bit is added to read data has been adopted as a method for detecting data corruption that occurs during data transfer between a keyboard and a keyboard control unit.

FIG. 1 is a diagram for explaining the structure of data with a 1-bit parity bit generated from a general keyboard.

In the figure, when a key is pressed on the keyboard 1, a parity generator 6 (PG) inside the keyboard 1 operates, adds a parity bit to the keystroke data, and sends the data onto the data line.

On the other hand, a parity checking section 7 (PC) inside the keyboard control section 2 which receives and receives data sent out on the data line detects whether or not there is data garbled on the data line.

The parity generator 6 generates parity bits so that the sum of all data bits and the parity bit becomes "O" in the even parity method, and "1°" in the odd parity method.

Further, the parity check unit 7 checks the validity of the parity bit for the data.

However, with such conventional parity checking methods, it is impossible to restore the data to correct data if multiple bits are garbled in the transferred data. There was a strong demand for recovery of corrupted data.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a data transfer/reading method that can detect garbled data or data leakage of multiple bits of data during data transfer, and transfer and read normal data.

A feature of the present invention is that the keyboard side generates a plurality of busy bits with a predetermined bit pattern each time data is input to indicate whether or not data has been transferred normally on the data line between the keyboard and the keyboard controller. On the other hand, on the control device side, the busy bit is read along with the data, and the data is read at least twice for the same manual data while checking the status of the busy bit to determine the validity of the read data.

Further, regarding data, the two read data before and after which are determined to be valid by checking the busy bit are compared, and when a match is detected, the data is treated as normally transferred data.

If the data is determined to be invalid by the busy bit check, or if the two data determined to be valid do not match, the data is re-read and a comparison is performed to determine whether the two sets of valid data match. It detects garbled data and imports only normal data to prevent data leaks, data omissions, and data corruption.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a diagram for explaining a data transfer/reading method between the keyboard 1 and the keyboard control section 2 when the present invention is used.

When no key is pressed on the keyboard 1, the busy bit 5 of the data sent from the keyboard 1 is all “
0''.

When a key is pressed, the busy bits are all "1" until the data is read by the keyboard control section 2 as valid data, and once the data is read by the control section as valid data, all the busy bits become "0". .

The busy bit 5, which has different states depending on data input and data reading on the control section side, is created by the busy bit creation section 8 (BG) of the keyboard 1.

Further, the data transferred when all the busy bits 5 are 0'O' is the same data as the last valid data.

The keyboard control unit 2 is connected to a busy check unit 9 (BC) that reads data on the data line at regular intervals and checks whether the busy bit satisfies a predetermined condition to determine the validity of the data. The data matching unit 10 compares two sets of data and takes in only the data when they match as normal data.

FIG. 3 is a diagram for explaining the operations of the keyboard 1 and the keyboard control section 2 shown in FIG. 2 described above.

A detailed explanation will be given below according to the drawings.

(a) When data transfer is normal When data and busy bits are read from the keyboard, FLAG (flag: instructs to read the same data at least twice in a row) is not set and the busy bit is 2 bits. If it is determined that the above values are 44 and 11 (all busy bits due to keystrokes are “°1°”), the data is considered valid, the FLAG is set, this data is stored, and the reading of the same data is started again. It is done.

(The above route is block 11, 12, 13, 15, 16
, 14).

The same data is then read again.

In this case, all busy bits are 0' because no key is pressed.

When the data and busy bit are read for the second time with FLAG already set, the busy bit is not 2 or more bits "1", and the data stored last time and the data read this time match.
It is determined that the read data has been transferred normally, and the FL
AG is reset.

As a result, the previously stored data is taken into another device (not shown), and key reading activation of the next data is performed.

As described above, in the present invention, even if the busy bit is corrupted within one bit, the data is read twice to find a match.
Capture valid data and prevent data loss.

Note that this route includes blocks 11, 12, 17, 18, 1
9, 20, 14.

Further, FIG. 4 shows a state in which the busy bit is reduced to 1 bit.

FIG. 4a shows the normal busy bit 21 and data 22 transferred from the board 1 when a key is pressed, and FIG.

(b) If two or more busy bits are corrupted, the data read from the keyboard and the busy bits are
If it is determined that two or more bits of busy bits are not "1" while LAG is not set, the data and busy bits are read again (the path is from block 11).
, 12, 13°14).

This operation is repeated until no more than two busy bits can be corrupted.

When the busy bit becomes less than 1 bit, FLAG is set, the data is stored as valid data, and then the data is read out many times until a match is found between this and the subsequently read data.

The above operations are performed in blocks 11, 12゜13.15.16
,14. lL12,17°18.14.

(e) If the busy bit (“1゜'1141, i7111) by keyboard keystroke is within 1 bit, then the busy bit (“011 7101”) that is read again
In the above case, the data read from the keyboard and the busy bit are first stored in blocks 11, 12, 13, 12, and 13, as in (a) above.
Routes 15, 16, and 14 are taken.

The re-read data and busy bits (two or more bits are garbled) are treated as invalid data if it is determined that the busy bits are two or more bits "1" while FLAG is set, and jl 1. Data re-reading is repeated until the AI busy bit becomes 1 bit or less (route at this time is 11, 12, 17, 14).
When the busy bit "1'" becomes less than 1 bit, it is determined whether the data matches the previously stored data.

If a match is detected (even if the busy bit is corrupted,
If the data is not corrupted) FLAG is reset,
The previously stored data is imported into another storage device, etc., and the next data key reading activation is performed (the above path includes blocks 11, 12, 17, 1B, 19, 20, 14).
).

If a mismatch is detected (if the data is also garbled),
The same data and busy bit key read activation is performed again, and this operation is repeated until the data matches the previously read and stored data. .......

) The state of this data and busy bit is shown in FIG.

FIG. 5A shows a normal state of data transferred from the keyboard 1, FIG. 5 shows a state where data is corrupted and is transferred to the keyboard control device 2, and FIG. The reading state is shown, and FIG. 5d shows the reading state again and again.

First, the data 24 in FIG. 5 transferred to the keyboard control device 2 is stored, and FLAG is set (the path in FIG.
).

The read data 25 shown in FIG.
17, 18, 140).

The correct data 26 shown in FIG. 5D that has been read out again is compared with the previously stored data 25, and since they match, the FLAG is reset, data 25 is taken in, and the next read data and busy bit are read out.

(The path in Fig. 3 includes blocks 11, 12, 1γ, 18,
19, 20°, and 14) As described above, in the present invention, the reading operation is repeated many times until a match with the previously read data is obtained.

In addition, if this discrepancy is repeated for example 5 times or more,
The keyboard or keyboard control device has a function to notify the operator of errors in data transfer.

As described above, according to the present invention, the data transferred from the keyboard is read out at least twice, and when a match is found, the data is imported into another storage device, etc., thereby preventing data leakage. Therefore, accurate data transfer can be performed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a keyboard and a keyboard control device for explaining a conventional data transfer reading method, and FIG. 2 is a diagram showing a keyboard and a keyboard for explaining a data transfer reading method according to an embodiment of the present invention. 3 is a flowchart 1 for explaining the present invention in detail, and FIG. 4 is a diagram showing a busy bit and data format for explaining bit extraction and bit generation in data transfer. FIG. 5 is a diagram showing busy bits and data formats for explaining the present invention in detail. Explanation of symbols, 1...Keyboard, 3...
・Key reading data, 5... Busy bit, 8
. . . Busy bit creation section, 9 . . . Busy bit inspection section, 10 . . . Data matching inspection section.

Claims (1)

[Claims] 1 In a data transfer/read method in which input data from a keyboard is transferred to a control device and read, the keyboard generates multiple bits of bit information each having a unique state when inputting data and after data is read by the control device. , the control device periodically reads the bit information together with the manual data, determines the validity of the read data from the state of the read bit information, and finds a match between the two previous and previous read data that are mutually determined to be valid. A data transfer reading method characterized in that when detected, the data is treated as normally transferred input data.