JP2653514B2 - Scan controller - Google Patents

Description

The present invention relates to a scan controller that generates a key code corresponding to a keystroke key by a key scan operation.
In particular, it relates to a method of transmitting a response signal from the scan controller to the host computer.

(Prior Art) In general, a scan controller sequentially executes three functions, that is, a command check function, a key scan check function, and a key code check function, in order to notify data inputted from a keyboard to a host CPU. The command check function polls data from the host CPU and executes command processing when a command is detected by this polling. This command processing includes checking of command contents, branching to various commands, command storage, execution of each command processing, and response (for example, data generated by the command processing).
Is transmitted, and the stored command is cleared.

The key scan check function includes a key scan process for reading a key arrangement of a keyboard to generate a key code corresponding to a keystroke key, and a check process for controlling the execution timing of the key scan. In other words, the key scan check function activates the key scan process at regular intervals (time determined by the CPU's interval timer), generates a key code by this key scan process, and stores the key code in the key code buffer. You.

The key code check function polls the key code to detect whether the key code is stored in the key code buffer.
Send the key code to U11.

Such a series of processes (the command check function, the key scan check function, and the key code check function) of the scan controller are executed within a time shorter than the key scan execution timing described above. This is because the above-described three functions are executed each time one key scan is performed, and the key code is transmitted to the host CPU.

However, when an error occurs in response transmission in command processing of the scan controller (response transmission is performed in a data transmission disabled state), it takes time for command processing to retransmit the response, and the key scan execution timing The series of processes described above may not be completed within the interval. This causes a failure in the overall operation condition of the scan controller, and causes a problem that a response or data input from the keyboard cannot be normally notified to the host CPU.

(Problems to be Solved by the Invention) The conventional scan controller has a drawback that if an error occurs in the response transmission of the command processing, the time required for the command processing is lengthened and the entire operating condition of the scan controller is impaired. Was.

The present invention has been made in view of such a point, and even if an error occurs in response to command processing, a scan controller that can reliably transmit a response without affecting the overall operation conditions of the scan controller. The purpose is to provide.

According to the present invention, a scan controller that generates a key code corresponding to a keystroke key by a key scan operation executes processing according to a command from a host computer. Command processing means for generating a response signal generated in the course of the command processing, storage means for storing the response signal generated by the command processing means, and storage means after the command processing of the command processing means is completed Response signal transmitting means for detecting whether a response signal is stored in the host computer, and transmitting the response signal to the host computer when the response signal is stored.

(Operation) In the scan controller, the response signal generated by the command processing is not directly transmitted to the host CPU but is temporarily stored in the storage unit. And
After completion of the command processing, it is detected whether or not a response signal is stored in the storage means. When the response signal is stored, the response signal is sent to the host computer. For this reason,
Even if the data cannot be transmitted during the command processing, the response signal does not need to be retransmitted during the command processing and can be simply stored in the storage means, without affecting the overall operating conditions of the scan controller. It is possible to transmit a response reliably.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration of a data processing system including a scan controller according to an embodiment of the present invention. host
The CPU 11 controls the operation of the entire system. The keyboard controller 12 and the scan controller 13 are provided with a keyboard control command (KBC control command) and a scan controller control command (SCC control command).
Control commands), and receives responses from the controllers 12 and 13.

The keyboard controller 12 includes a CPU and an RA
M and ROM, and interfaces between the host CPU 11 and the scan controller 13.
That is, the keyboard controller 12 receives the KBC control command and the SCC control command sent from the host CPU 11, executes the KBC control command, transmits the SCC control command, receives a response signal (SCC response) from the scan controller 13, Sends the response and SCC response, receives the key code, and sends the key code.

The scan controller 13 has a keyboard (not shown)
The key code corresponding to the key-pressing key is generated by a key scan operation.
It is composed of a RAM 13b and a ROM 13c. The scan controller 13 receives an SCC control command, executes the SCC control command, transmits an SCC response, and transmits a key code.

FIG. 2 shows the contents of information stored in the RAM 13c of the scan controller 13. The ROM 13c includes a program 21 for executing a start function, a program 22 for a table function, and a program 2 for executing an SCC processing function.
3, having a program 24 for executing a data receiving function, a program 25 for executing a command processing function, a program 26 for executing a data transmitting function, and a program 27 for executing a key scan processing function ing.

The program 21 for the start function functions as a program start pointer at the time of energization, and thereby the program 23 for the SCC processing function is started. The program 22 for the table function has a key scan code table including parameter information for converting information obtained by key scan into a key code, a command branch table, and work default information.

The program 23 for the SCC processing function is for executing the operation control of the entire program, and includes the main functions of the scan controller, that is, the initialization function (only when power is supplied), the command check function, and the response check. There is a function, a key scan check function, and a key code check function. The program 24 for the data reception function is for receiving one byte of data and storing it in the data reception buffer when it is detected that data is sent by polling in the command check of the SCC processing program 23. Program.

The program 25 for the command processing function is for executing the corresponding command processing when the received data is determined to be a command by the command check after data reception, and in the course of this command processing, A response is generated.

The program 26 for the data transmission function is a program for reading transmission data from the data transmission buffer and transmitting one byte of data under the condition that the data transmission is possible. The program 27 for the key scan processing function reads a key arrangement of a keyboard, generates a key code corresponding to a keystroke key, and stores it in a key code buffer.

FIG. 3 shows the contents of information stored in the RAM 13b of the scan controller 13. The RAM 13b has a register area 31 including an area 32 functioning as a put pointer, a stack area 33, a work area 34, and a flag area 35.

The register area 31 is an area in which various register information necessary for the control operation of the CPU 13a is stored. An area 32 functioning as a put pointer is a part of the register area 32, and the area 32 stores information for instructing a buffer for storing a response.

The stack area 33 is an area in which various types of stack information necessary for the control operation of the CPU 13a are stored. The work area 34
This area is used as a work area when the CPU 13a operates, and a response is stored in a buffer in the work area. The flag area 35 is an area for storing flag information used when the CPU 13a operates.

FIG. 4 shows the contents of the work area 34. This work area
34 has first to sixth buffer areas 41 to 47 and an area 47 functioning as a gate pointer.

The first buffer area 41 is a response storage area in which the first response is stored when storing the response. Similarly, the second to sixth buffer areas 42 to 46 are response storage areas in which the second to sixth responses are respectively stored. These buffer areas 41 to 46
Stores clear data when no response is generated.

The area 47 functioning as a get pointer stores information indicating from which buffer a response is read.

Next, the operation of the scan controller 13 will be described with reference to the flowchart of FIG. First, at the time of energization, the program 22 for the SCC processing function is started by the program 21 for the start function in the ROM 13c, and the work area 34 and the flag area 35 of the RAM 13b are first initialized (step A1). When the initialization is completed, a command check function is activated (step A2). This command check function is for detecting whether or not data is sent from the CPU 11 via the keyboard controller 12, and if there is data, the data is checked by a program for the data reception function of the ROM 13c. Reception is performed. If the received data is not a command or a command parameter, the command check process is terminated without any action and the response check process (step
Go to A3). On the other hand, when the received data is a command or a command parameter, the program 25 for the command processing function of the ROM 13c is started, and the corresponding command processing is executed (step A4). In the course of this command processing, a response is generated, and the response is stored in the response buffer shown in FIG.

Here, FIG. 6 shows a flowchart of the version number reading process as an example of the command process in step A4. In FIG. 6, when command processing is started. First, a response signal (ACK), that is, a response is stored (step B1). This response is a response to the reception of the command. Since this is the first response, the first buffer area 41 in FIG.
Is stored in The processing of step B1 is executed according to the processing order as shown in FIG. That is, first, a response is prepared (step C1), and the prepared response is stored in the buffer indicated by the put pointer of the RAM 13b, that is, the first buffer 41 (step C1).
2). Next, the content of the put pointer is updated by +1 (step C3), and the clear data is written to the buffer designated by the updated put pointer, that is, the second buffer 42. As a result, the second buffer 42 is initialized.

Next, the version number set (step B2) and the keyboard type set (step
The processing of B3) is executed in the same manner as in step B1, and the prepared responses are stored in predetermined buffers.

Thus, when the command processing is completed, the response check (step A3) shown in FIG. 5 is started. In this response check, the buffers 41 to 41 shown in FIG.
It is checked whether or not a response is stored in 46. If no response is stored, the key scan check (A6) is executed without doing anything. On the other hand, when the response is stored, the transmission of the response is executed (step A5).

Here, the processes of the response check (step A3) and the response transmission (step A5) are shown in FIGS.
This will be described with reference to the flowchart in FIG.

When the response check is started, first, the contents of the get pointer 47 are read (step D1), and then the data stored in the buffer specified by the get pointer is read. Then, the presence or absence of a response is determined (step D3). The determination of the presence or absence of the response is performed by detecting whether the data read from the buffer is clear data. If there is no response, that is, if the data read from the buffer is clear data, nothing is executed and the response check (step A3) in FIG. 5 ends. On the other hand, if there is a response, that is, if the data read from the buffer is different from the clear data, after performing a get pointer read (step D4) and a buffer read (step D6) for transmitting the response, the data transmission program of the ROM 13c is executed. The response is transmitted by activating 26 (step D6).

Next, it is determined whether or not an error has occurred in the transmission of this response (step D7). If an error has occurred, the response transmission is terminated without doing anything. In this case, even if an error occurs, the response is stored in the buffer, so that the response can be transmitted when the next response is transmitted.

When the response transmission is completed normally, the processing of steps D8 to D11 in FIG. 9 is executed. That is, the contents of the get pointer 47 are read out to the register 31 (step
D8), the buffer specified by the get pointer 47 is cleared (step D9). Then register 31
Is updated by +1 (step D10), the updated contents of the register 31 are stored in the get pointer 47 (step D11).

In this way, the response check (Step A3)
When the process of transmitting the response (Step A5) is completed, a key scan check (Step A6) is started.

This key scan check detects a timing determined by an internal timer of the CPU 13a, and executes a key scan process (step A8) at that timing. If it is not the key scan timing, a key code check (step A7) is executed.

In the key scanning process (step A8), the key arrangement of the keyboard is read, and a key code corresponding to the keystroke key is generated. Then, the key code is stored in the work area 34. Key code check (Step A7)
Then, the presence / absence of a key code is determined. If the key code is not stored in the work area 34, the process returns to step A2. If the key code is stored, the key code transmission process (step A9) is executed. You.

As described above, the operation of the scan controller is executed by repeatedly starting the command check, the response check, the key scan check, and the key code check.

In the scan controller 13, a response signal (response) generated by command processing is
The data is not directly transmitted to the CPU 11 but is temporarily stored in the storage unit. After completion of the command processing, it is detected whether or not a response signal is stored in the storage means. When the response signal is stored, the response signal is sent to the host computer. For this reason, even if the data transmission is disabled during the command processing, it is not necessary to retransmit the response signal during the command processing, and it is sufficient to simply store the response signal in the storage means, which affects the overall operation conditions of the scan controller. It is possible to send a response without any problem.

[Effects of the Invention] As described above, according to the present invention, even if an error occurs in the transmission of a command processing response, the overall operation conditions of the scan controller are not affected.
The response can be transmitted reliably.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration including a scan controller according to an embodiment of the present invention. FIG. 2 is a block diagram showing an RO provided in the scan controller shown in FIG.
FIG. 3 is a diagram showing the contents stored in M, FIG. 3 is a diagram showing the contents stored in the RAM provided in the scan controller shown in FIG. 1, and FIG. 4 is a diagram showing the contents stored in the RAM shown in FIG. FIGS. 5 to 9 are diagrams for explaining the operation of the scan controller shown in FIG. 1, respectively. 11: Host CPU, 12: Keyboard controller, 13
…… Key scan controller, 13a …… CPU, 13b …… R
AM, 13c …… ROM.

Claims (1)

(57) [Claims] 1. A scan controller for generating a key code corresponding to a keystroke key by a key scan operation, executes a process corresponding to a command from a host computer, and generates a response signal generated in the process of the command processing. Command processing means, storage means for storing a response signal generated by the command processing means, and detecting whether a response signal is stored in the storage means after the command processing of the command processing means is completed. And a response signal transmitting means for transmitting a response signal to the host computer when the response signal is stored.