如果你的记性好，也许看到前面有一些键盘初始化了，但那里的初始化是设置南桥接收键盘数据输入和输出而已，只是一个接口，或者是一个代理。在这里才是开始真正初始化键盘，让键盘工作在合适的方式。在电脑里，显示卡输出信息给人看，而键盘扮演着另一个角色，就是让人们可以输入东西，控制电脑做各种各样的事情。虽然电脑的历史也有60年了，并且技术也在飞速地发展，但是键盘还是作为重要的输入方式。希望我们大家能发明一种更好的输入方式，语音输入？还是脑电波输入？也许很快就到来。下面来仔细地分析键盘初始化的实现，代码如下：
int kbd_initialize(void)
{
int status;
int count;
/* Flush the buffer */
kbd_clear_input();
上面清除键盘输入缓冲里的数据。由于键盘采用环形缓冲作为输入缓冲区，如果不清除输入的内容，就不是当时按键的内容了。
/*
* Test the keyboard interface.
* This seems to be the only way to get it going.
* If the test is successful a x55 is placed in the input buffer.
*/
kbd_write_command_w(KBD_CCMD_SELF_TEST);
if (kbd_wait_for_input() != 0x55) {
printf("Self test cmd failed,ignored!\n");
//return 1;
}
上面进行键盘测试。
/*
* Perform a keyboard interface test. This causes the controller
* to test the keyboard clock and data lines. The results of the
* test are placed in the input buffer.
*/
kbd_write_command_w(KBD_CCMD_KBD_TEST);
if (kbd_wait_for_input() != 0x00) {
printf("KBD_TEST cmd failed,ignored!\n");
//return 1;
}
上面进行键盘接口测试。
/*
* Enable the keyboard by allowing the keyboard clock to run.
*/
kbd_write_command_w(KBD_CCMD_KBD_ENABLE);
上面设置键盘时钟开始运行。
/*
* Reset keyboard. If the read times out
* then the assumption is that no keyboard is
* plugged into the machine.
* This defaults the keyboard to scan-code set 2.
*
* Set up to try again if the keyboard asks for RESEND.
*/
count = 0;
do {
kbd_write_output_w(KBD_CMD_RESET);
status = kbd_wait_for_input();
if (status == KBD_REPLY_ACK)
break;
if (status != KBD_REPLY_RESEND) {
printf("reset failed\n");
if (++count > 1) break;
//return 2;
}
} while (1);
if (kbd_wait_for_input() != KBD_REPLY_POR) {
printf("NO POR, ignored!\n");
//return 3;
}
上面进行键盘复位设置。
/*
* Set keyboard controller mode. During this, the keyboard should be
* in the disabled state.
*
* Set up to try again if the keyboard asks for RESEND.
*/
count = 0;
do {
kbd_write_output_w(KBD_CMD_DISABLE);
status = kbd_wait_for_input();
if (status == KBD_REPLY_ACK)
break;
if (status != KBD_REPLY_RESEND){
printf("disable failed\n");
if (++count > 1) break;
//return 4;
}
} while (1);
kbd_write_command_w(KBD_CCMD_WRITE_MODE);
kbd_write_output_w(KBD_MODE_KBD_INT
| KBD_MODE_SYS
| KBD_MODE_DISABLE_MOUSE
| KBD_MODE_KCC);
上面设置键盘的控制模式。
#if 1
/* ibm powerpc portables need this to use scan-code set 1 -- Cort */
if (!(kbd_write_command_w_and_wait(KBD_CCMD_READ_MODE) & KBD_MODE_KCC))
{
/*
* If the controller does not support conversion,
* Set the keyboard to scan-code set 1.
*/
kbd_write_output_w(0xF0);
kbd_wait_for_input();
kbd_write_output_w(0x01);
kbd_wait_for_input();
}
#endif
if (kbd_write_output_w_and_wait(KBD_CMD_ENABLE) != KBD_REPLY_ACK) {
return 5;
}
上面设置键盘输入的编码方式。
/*
* Finally, set the typematic rate to maximum.
*/
if (kbd_write_output_w_and_wait(KBD_CMD_SET_RATE) != KBD_REPLY_ACK) {
return 6;
}
if (kbd_write_output_w_and_wait(0x00) != KBD_REPLY_ACK) {
return 7;
}
上面设置键盘的按键速度。
return 0;
}
通过上面的初始化设置，就可以接收键盘输入了。
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