JPS5911931B2 - Keyboard control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a matrix scan type keyboard control system.

Conventionally, a liftware scanning method is known as a keyboard control method for detecting the position of a key operated on a keyboard matrix.

This is done by ORing the keyboard matrix output and polling it using software, or issuing an interrupt using hardware. This method requires at least one IC to OR the keyboard matrix output. In order to remove this IC, it is conceivable to perform software scanning of the keyboard matrix at certain time intervals, but this would require a large amount of software time for processing and would place an excessive burden on the software. The present invention has been made in view of these problems, and an object of the present invention is to provide a keyboard control method that can reduce the amount of hardware and the burden on software. Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 100 is a microprocessor (CUP
).

101 is an address decoder (DCDR), 102, 10
3 is an AND gate, 104 is a register (REG), 10
5 is a driver (DRVR), 106 is a keyboard matrix, and IOT is an internal register (A-REG) of the microprocessor 100.

The keyboard matrix 106 has eight input lines 104.
-0, 104-1 to 104-T and eight output lines 105
-0, 105-1 to 105-7. The register 104 has the same number of bits as the input lines of the keyboard matrix 106, and the output end of each bit is connected to the corresponding input line 104-0, 104-1 to 104-T. The driver 105 has the same number of input terminals as the output lines of the keyboard matrix 106, and connects each input terminal to a corresponding output line 105-0, 105-1, ~1.
Connected to 05-7. When the register 104 is supplied with the clock signal 15 from the AND gate 103, the contents of the internal register 107 are written via the bus line 10. When the driver 105 receives an enable signal from the AND gate 102, the driver 105 activates the keyboard matrix 10.
6 to the internal register 107 via the bus line 10.
Send to. AND gate 102 is address decoder 1
When the output signal 12 of 01 and the read (READ) signal 17 from the microprocessor 100 are input, the enable signal 14 is output. AND gate 103 outputs clock signal 15 when output signal 13 of address decoder 101 and write (WRITE) signal 16 from microprocessor 100 are input.

Address decoder 101 decodes address information 11 from microprocessor 100 and selectively outputs output signals 12 and 13. In addition, keyboard matrix 10
A key is arranged at each intersection of the input lines 104-0, 104-1 to 104-7 and the output lines 105-0, 105-1 to 105-7 of No. 6, and each intersection is normally in an off state.
It turns on when the key is operated, that is, pressed.

In this embodiment, output lines 105-0, 105-1 to 105
-7 output is normally (off state) logic ゜1'',
In addition, the output of each bit of the register 104 is set to the normal (off state) logic 0I. When a key is operated, the output of the output line passing through the intersection corresponding to the operated key becomes logic 0I. In other words, logic ゞ0
'5 is set to be significant. Then, the microprocessor 100 performs the operation shown in the flowchart of FIG.
This causes the microprocessor 100 to detect the operated key, that is, the position of the key operated key on the keyboard matrix 106 using software. Hereinafter, the operation of detecting the position where a key is operated by the microprocessor 100 will be explained with reference to the flowchart of FIG.

First, before operating the keyboard, the microprocessor 100 writes logic O'' data to all bits in the internal register 107 (step 200), and writes the data in the internal register 107 to the register 104 (step 2).
01).

This causes all bits of register 104 to become logic 0''.
Therefore, if a key on the keyboard matrix 106 is selected, the output lines 105-0, 105-1 to 105
-7 either output becomes logic "O". Therefore, in order to determine whether or not a key is being operated, the microprocessor 100 sends the keyboard matrix 1 from the driver 105 to the internal register 107 via the bus line 10.
06 is read (step 202), and it is determined whether or not the read output contains logic 'O' bits, in other words, whether all bits are logic '1' (step 203).

If all bits are logic 1'', that is, if no key is operated, the operation of the microprocessor 100 returns to step 202. Therefore, steps 202,
Step 203 is repeated until a key is operated. In step 203, when the microprocessor 100 detects that the read output of the keyboard matrix 106 contains a logic 02 bit, that is, when it detects that a key has been operated, it determines which key was operated. To make the determination, first, data is stored in the internal register 107 in which only the least significant bit is logic 'O', that is, '11...10'.
(Step 204), and the data is written to the register 104 via the bus line 10 (Step 205).

Then, the microprocessor 100 reads the output of the keyboard matrix 106 located on the input line 104-0 from the driver 105 into the internal register 107 (step 206), and determines whether the read data contains a logic 0'' bit. In other words, it is determined whether all the bits are logic 1 (step 207).If all the bits are logic 1, the microprocessor 100 sets the data in the register 104 to logic ``O''. The data obtained by shifting the bit position by one digit, ie, "11...101" is written into the internal register 107 (step 208), and the operation returns to step 205. The microprocessor 100 then reads the output of the keyboard matrix 106 located on the next input line 104-1 and makes a determination. Therefore,
The operations from step 205 to step 208 are repeated until the bit of logic SO'' is detected in step 207. When the bit of logic SO'' is detected in step 207, the microprocessor 100 then registers internal register 107. The key being operated is identified based on the data stored in the data stored in the driver 105 and the data read from the driver 105, and the key being operated is displayed and the instruction of the operated key is executed.After this is completed, the operation proceeds to step 200. Return to
Waits for the next keystroke. As is clear from the above, according to the present invention, a key-in request, that is, whether or not a key has been operated is determined in a loop of steps 202 and 203.

Conventionally, this has been done in a loop of steps 205 to 208, but in this loop, the loop must be executed eight times just to scan the keyboard matrix 106 mentioned above. Therefore, when considered simply, according to the present invention, key-in requests can be determined in a loop with a short number of steps, and polling can be performed at a frequency as low as 1/8, which reduces the burden on the software. This allows more time to execute other processes.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining an embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of the embodiment. 100...Microprocessor, 101...
...Decoder, 102, 103...And gate, 104...Register, 105...
- Driver, 106...Keyboard matrix, 107...Internal register.

Claims (1)

[Claims] 1 comprising a processor, a keyboard matrix, a register provided by connecting each bit to each input line of the keyboard matrix, and a driver provided connected to each output line of the keyboard matrix, Significant data is written from the processor to all bits of the keyboard matrix, and the processor detects the key-in state by reading the output of the keyboard matrix at predetermined intervals via the driver, and detects the key-in state by reading the output of the keyboard matrix at predetermined intervals. When the processor detects the bit, the processor writes data in which only one bit is made significant to the register, sequentially changing the significant bit position, and each time writes data to the input line specified by the register. The output of the keyboard matrix is read through the driver, and when a significant bit is detected in the read output, the keys of the keyboard matrix are operated based on the data used to write the register and the read data. A keyboard control method characterized by differentiating positions.