/* terminate a transmission if we have */
inhibit();
- wait_us(100); // 100us [4]p.13, [5]p.50
+ wait_us(100); // [5]p.54
/* 'Request to Send' and Start bit */
data_lo();
- clock_hi();
- WAIT(clock_lo, 10000, 1); // 10ms [5]p.50
+ wait_us(100);
+ clock_hi(); // [5]p.54 [clock low]>100us [5]p.50
+ WAIT(clock_lo, 10000, 1); // [5]p.53, -10ms [5]p.50
/* Data bit[2-9] */
for (uint8_t i = 0; i < 8; i++) {
/* Stop bit */
wait_us(15);
data_hi();
+ WAIT(clock_hi, 50, 6);
+ WAIT(clock_lo, 50, 7);
/* Ack */
- WAIT(data_lo, 50, 6);
- WAIT(clock_lo, 50, 7);
+ WAIT(data_lo, 50, 8);
/* wait for idle state */
- WAIT(clock_hi, 50, 8);
- WAIT(data_hi, 50, 9);
+ WAIT(clock_hi, 50, 9);
+ WAIT(data_hi, 50, 10);
// clear buffer to get response correctly
recv_data = 0xFFFF;
}
}
+ //dprintf("i%04X ", ibmpc_isr_debug); ibmpc_isr_debug = 0;
dprintf("r%02X ", ret);
return ret;
}
void ibmpc_host_isr_clear(void)
{
+ ibmpc_isr_debug = 0;
+ ibmpc_protocol = 0;
+ ibmpc_error = 0;
isr_state = 0x8000;
recv_data = 0xFFFF;
}
+#define LO8(w) (*((uint8_t *)&(w)))
+#define HI8(w) (*(((uint8_t *)&(w))+1))
// NOTE: With this ISR data line can be read within 2us after clock falling edge.
// To read data line early as possible:
// write naked ISR with asembly code to read the line and call C func to do other job?
if (isr_state == 0x8000) {
timer_start = t;
} else {
- // should not take more than 1ms
- if (timer_start != t && (uint8_t)(timer_start + 1) != t) {
+ // This gives 2.0ms at least before timeout
+ if ((uint8_t)(t - timer_start) >= 3) {
+ ibmpc_isr_debug = isr_state;
ibmpc_error = IBMPC_ERR_TIMEOUT;
- //goto ERROR;
- // timeout error recovery by clearing isr_state?
- timer_start = t;
- isr_state = 0x8000;
+ goto ERROR;
+
+ // timeout error recovery - start receiving new data
+ // it seems to work somehow but may not under unstable situation
+ //timer_start = t;
+ //isr_state = 0x8000;
}
}
goto NEXT;
} else {
// XT_Clone-done
+ ibmpc_isr_debug = isr_state;
isr_state = isr_state>>8;
ibmpc_protocol = IBMPC_PROTOCOL_XT_CLONE;
goto DONE;
goto NEXT;
} else {
// no stop bit: XT_IBM-done
+ ibmpc_isr_debug = isr_state;
isr_state = isr_state>>8;
ibmpc_protocol = IBMPC_PROTOCOL_XT_IBM;
goto DONE;
case 0b01010000:
case 0b11010000:
// AT-done
- // DO NOT check stop bit. Zenith Z-150(AT) asserts stop bit as low for no reason.
- // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#zenith-z-150-beige
// TODO: parity check?
+ ibmpc_isr_debug = isr_state;
+ // stop bit check
+ if (isr_state & 0x8000) {
+ ibmpc_protocol = IBMPC_PROTOCOL_AT;
+ } else {
+ // Zenith Z-150 AT(beige/white lable) asserts stop bit as low
+ // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#zenith-z-150-beige
+ ibmpc_protocol = IBMPC_PROTOCOL_AT_Z150;
+ }
isr_state = isr_state>>6;
- ibmpc_protocol = IBMPC_PROTOCOL_AT;
goto DONE;
break;
case 0b01100000:
ibmpc_error = IBMPC_ERR_FF;
goto ERROR;
}
- if ((recv_data & 0xFF00) != 0xFF00) {
+ if (HI8(recv_data) != 0xFF && LO8(recv_data) != 0xFF) {
// buffer full
ibmpc_error = IBMPC_ERR_FULL;
goto ERROR;