ibmpc: Change ISR code
It reads data line within 3us
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tmk
parent
e7d6d24c17
commit
c2e8c0d43e
1 changed files with 99 additions and 104 deletions
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@ -41,6 +41,7 @@ POSSIBILITY OF SUCH DAMAGE.
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#include <stdbool.h>
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#include <avr/interrupt.h>
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#include <util/atomic.h>
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#include "ringbuf.h"
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#include "ibmpc.h"
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#include "debug.h"
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@ -88,9 +89,8 @@ void ibmpc_host_enable(void)
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void ibmpc_host_disable(void)
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{
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// TODO: test order? uneeded interrupt happens by making clock lo
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inhibit();
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IBMPC_INT_OFF();
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inhibit();
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}
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int16_t ibmpc_host_send(uint8_t data)
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@ -158,128 +158,123 @@ ERROR:
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return -1;
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}
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/*
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* Receive data from keyboard with ISR
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*/
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static volatile int16_t recv_data = -1;
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static volatile uint16_t isr_data = 0x8000;
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void ibmpc_host_isr_clear(void)
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{
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isr_data = 0x8000;
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}
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int16_t ibmpc_host_recv(void)
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{
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int16_t data = 0;
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ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
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data = recv_data;
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recv_data = -1;
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}
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if (data != -1) {
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dprintf("r%04X ", data);
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}
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return data;
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}
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int16_t ibmpc_host_recv_response(void)
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{
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// Command may take 25ms/20ms at most([5]p.46, [3]p.21)
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uint8_t retry = 25;
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while (retry-- && ringbuf_is_empty(&rb)) {
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int16_t data = -1;
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while (retry-- && (data = ibmpc_host_recv()) == -1) {
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wait_ms(1);
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}
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int16_t data = ringbuf_get(&rb);
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if (data != -1) dprintf("r%02X ", data);
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return data;
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}
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/* get data received by interrupt */
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int16_t ibmpc_host_recv(void)
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{
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int16_t data = ringbuf_get(&rb);
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if (data != -1) dprintf("r%02X ", data);
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return data;
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}
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/*
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* Receive data from keyboard with ISR
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*/
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static enum {
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START,
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BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7,
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PARITY,
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STOP, } isr_state = START;
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static uint8_t isr_data = 0;
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static uint8_t isr_parity = 1;
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static uint16_t isr_time = 0;
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void ibmpc_host_isr_clear(void)
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{
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isr_state = START;
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isr_data = 0;
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isr_parity = 1;
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isr_time = 0;
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}
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ISR(IBMPC_INT_VECT)
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{
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uint8_t dbit = IBMPC_DATA_PIN&(1<<IBMPC_DATA_BIT);
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uint8_t dbit;
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dbit = IBMPC_DATA_PIN&(1<<IBMPC_DATA_BIT);
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isr_data = isr_data>>1;
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if (dbit) isr_data |= 0x8000;
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// Reset state when taking more than 1ms
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if (isr_time && timer_elapsed(isr_time) > 1) {
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ibmpc_error = IBMPC_ERR_TIMEOUT | IBMPC_ERR_RECV | isr_state;
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isr_state = START;
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isr_data = 0;
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isr_parity = 1;
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}
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isr_time = timer_read();
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switch (isr_state) {
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case START:
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if (ibmpc_protocol == IBMPC_PROTOCOL_XT) {
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// ignore start(0) bit
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if (!dbit) return;
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} else {
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if (dbit)
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goto ERROR;
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}
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// isr_data:
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// 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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// -----------------------------------------------------
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// Initial: *1 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0
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// XT IBM: b7 b6 b5 b4 b3 b2 b1 b0 | s1 s0 *1 0 0 0 0 0 after receiving **
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// XT Clone: b7 b6 b5 b4 b3 b2 b1 b0 | s1 *1 0 0 0 0 0 0 after receiving
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// AT: st pr b7 b6 b5 b4 b3 b2 | b1 b0 s0 *1 0 0 0 0 after receiving
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// AT**: pr b7 b6 b5 b4 b3 b2 b1 | b0 s0 *1 0 0 0 0 0 before stop bit **
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//
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// x x x x x x x x | 0 0 0 0 0 0 0 0 midway(0-7 bits received)
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// x x x x x x x x | 1 0 0 0 0 0 0 0 midway(8 bits received)
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// x x x x x x x x | 0 1 0 0 0 0 0 0 XT IBM-midway or AT-midway
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// x x x x x x x x | 1 1 0 0 0 0 0 0 XT Clone-done
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// x x x x x x x x | 0 0 1 0 0 0 0 0 AT-midway
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// x x x x x x x x | 1 0 1 0 0 0 0 0 XT IBM-done or AT-midway **
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// x x x x x x x x | x 1 1 0 0 0 0 0 illegal
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// x x x x x x x x | x x 0 1 0 0 0 0 AT-done
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// x x x x x x x x | x x 1 1 0 0 0 0 illegal
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// other states than avobe illegal
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//
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// **: AT can take same as end sate of XT IBM(1010 000) when b0 is 1,
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// to discriminate between them we will have to wait a while for stop bit.
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//
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// mask for isr_data:
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// 0x00A0(1010 0000) when XT IBM
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// 0x00C0(1100 0000) when XT Clone
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// 0x0010(xx01 0000) when AT
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//
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switch (isr_data & 0xFF) {
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case 0b00000000:
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case 0b10000000:
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case 0b01000000:
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case 0b00100000:
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// midway
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return;
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break;
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case BIT0:
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case BIT1:
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case BIT2:
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case BIT3:
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case BIT4:
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case BIT5:
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case BIT6:
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case BIT7:
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isr_data >>= 1;
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if (dbit) {
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isr_data |= 0x80;
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isr_parity++;
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}
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if (isr_state == BIT7 && ibmpc_protocol == IBMPC_PROTOCOL_XT) {
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if (!ringbuf_put(&rb, isr_data)) {
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ibmpc_error = IBMPC_ERR_FULL;
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goto ERROR;
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}
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ibmpc_error = IBMPC_ERR_NONE;
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case 0b11000000:
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// XT Clone-done
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recv_data = (isr_data>>8) & 0xFF;
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goto DONE;
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break;
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case 0b10100000:
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// XT IBM-done or AT-midway
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// wait and check for clock of AT stop bit
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if (wait_clock_hi(100) && wait_clock_lo(100)) { // FIXME this makes ISR prologe long
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// AT-midway
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return;
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} else {
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// XT-IBM-done
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recv_data = (isr_data>>8) & 0xFF;
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goto DONE;
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}
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break;
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case PARITY:
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if (dbit) {
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if (!(isr_parity & 0x01))
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goto ERROR;
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} else {
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if (isr_parity & 0x01)
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goto ERROR;
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}
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break;
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case STOP:
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if (!dbit)
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goto ERROR;
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if (!ringbuf_put(&rb, isr_data)) {
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ibmpc_error = IBMPC_ERR_FULL;
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goto ERROR;
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}
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ibmpc_error = IBMPC_ERR_NONE;
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case 0b00010000:
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case 0b10010000:
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case 0b01010000:
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case 0b11010000:
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// AT-done
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recv_data = (isr_data>>6) & 0xFF;
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goto DONE;
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break;
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default:
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goto ERROR;
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case 0b01100000:
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case 0b11100000:
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case 0b00110000:
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case 0b10110000:
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case 0b01110000:
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case 0b11110000:
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default: // xxxx_oooo(any 1 in low nibble)
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recv_data = isr_data;
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break;
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}
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goto NEXT;
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ERROR:
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ibmpc_error |= isr_state;
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ibmpc_error |= IBMPC_ERR_RECV;
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ringbuf_reset(&rb);
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DONE:
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isr_state = START;
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isr_data = 0;
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isr_parity = 1;
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isr_time = 0;
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return;
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NEXT:
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isr_state++;
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// TODO: buffer for recv_data
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isr_data = 0x8000; // clear to next data
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return;
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}
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