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Diffstat (limited to 'tmk_core/protocol/ibm4704.c')
-rw-r--r--tmk_core/protocol/ibm4704.c39
1 files changed, 18 insertions, 21 deletions
diff --git a/tmk_core/protocol/ibm4704.c b/tmk_core/protocol/ibm4704.c
index a10a5e74d..a2c670047 100644
--- a/tmk_core/protocol/ibm4704.c
+++ b/tmk_core/protocol/ibm4704.c
@@ -104,50 +104,47 @@ uint8_t ibm4704_recv_response(void)
return rbuf_dequeue();
}
+uint8_t ibm4704_recv(void)
+{
+ if (rbuf_has_data()) {
+ return rbuf_dequeue();
+ } else {
+ return -1;
+ }
+}
+
/*
Keyboard to Host
----------------
Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part.
- ____ __ __ __ __ __ __ __ __ __ ________
-Clock \____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/
+ ____ __ __ __ __ __ __ __ __ __ _______
+Clock \_____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/
____ ____ ____ ____ ____ ____ ____ ____ ____ ____
Data ____/ X____X____X____X____X____X____X____X____X____X________
Start 0 1 2 3 4 5 6 7 P Stop
Start bit: can be long as 300-350us.
Inhibit: Pull Data line down to inhibit keyboard to send.
-Timing: Host reads bit while Clock is hi.
+Timing: Host reads bit while Clock is hi.(rising edge)
Stop bit: Keyboard pulls down Data line to lo after 9th clock.
*/
-uint8_t ibm4704_recv(void)
-{
- if (rbuf_has_data()) {
- return rbuf_dequeue();
- } else {
- return -1;
- }
-}
-
ISR(IBM4704_INT_VECT)
{
static enum {
- INIT, START, BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY,
- } state = INIT;
+ STOP, BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY
+ } state = STOP;
// LSB first
static uint8_t data = 0;
// Odd parity
static uint8_t parity = false;
ibm4704_error = 0;
- // return unless falling edge
- if (clock_in()) { goto RETURN; } // why this occurs?
- state++;
- switch (state) {
- case START:
+ switch (state++) {
+ case STOP:
// Data:Low
- WAIT(data_hi, 10, state);
+ WAIT(data_lo, 10, state);
break;
case BIT0:
case BIT1:
@@ -182,7 +179,7 @@ ERROR:
while (ibm4704_send(0xFE)) _delay_ms(1); // resend
xprintf("R:%02X%02X\n", state, data);
DONE:
- state = INIT;
+ state = STOP;
data = 0;
parity = false;
RETURN: