*/
/*
-Primitive PS/2 Library for AVR
-==============================
-Host side is only supported now.
-Synchronous USART is used to receive data by hardware process
-rather than interrupt. During V-USB interrupt runs, CLOCK interrupt
-cannot interpose. In the result it is prone to lost CLOCK edge.
+ * PS/2 protocol USART version
+ */
-
-I/O control
------------
-High state is asserted by internal pull-up.
-If you have a signaling problem, you may need to have
-external pull-up resisters on CLOCK and DATA line.
-
-
-PS/2 References
----------------
-http://www.computer-engineering.org/ps2protocol/
-http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
-*/
#include <stdbool.h>
-#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "ps2.h"
-#include "debug.h"
+#include "print.h"
#define WAIT(stat, us, err) do { \
uint8_t ps2_error = PS2_ERR_NONE;
-static inline void clock_lo(void);
-static inline void clock_hi(void);
-static inline bool clock_in(void);
-static inline void data_lo(void);
-static inline void data_hi(void);
-static inline bool data_in(void);
-static inline uint16_t wait_clock_lo(uint16_t us);
-static inline uint16_t wait_clock_hi(uint16_t us);
-static inline uint16_t wait_data_lo(uint16_t us);
-static inline uint16_t wait_data_hi(uint16_t us);
-static inline void idle(void);
-static inline void inhibit(void);
static inline uint8_t pbuf_dequeue(void);
static inline void pbuf_enqueue(uint8_t data);
static inline bool pbuf_has_data(void);
void ps2_host_init(void)
{
- idle();
+ idle(); // without this many USART errors occur when cable is disconnected
PS2_USART_INIT();
PS2_USART_RX_INT_ON();
+ // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20)
+ //_delay_ms(2500);
}
uint8_t ps2_host_send(uint8_t data)
{
- uint8_t res = 0;
bool parity = true;
ps2_error = PS2_ERR_NONE;
/* terminate a transmission if we have */
inhibit();
- _delay_us(100);
+ _delay_us(100); // [4]p.13
- /* start bit [1] */
+ /* 'Request to Send' and Start bit */
data_lo();
clock_hi();
- WAIT(clock_lo, 15000, 1);
- /* data [2-9] */
+ WAIT(clock_lo, 10000, 10); // 10ms [5]p.50
+
+ /* Data bit[2-9] */
for (uint8_t i = 0; i < 8; i++) {
_delay_us(15);
if (data&(1<<i)) {
WAIT(clock_hi, 50, 2);
WAIT(clock_lo, 50, 3);
}
- /* parity [10] */
+
+ /* Parity bit */
_delay_us(15);
if (parity) { data_hi(); } else { data_lo(); }
WAIT(clock_hi, 50, 4);
WAIT(clock_lo, 50, 5);
- /* stop bit [11] */
+
+ /* Stop bit */
_delay_us(15);
data_hi();
- /* ack [12] */
+
+ /* Ack */
WAIT(data_lo, 50, 6);
WAIT(clock_lo, 50, 7);
WAIT(clock_hi, 50, 8);
WAIT(data_hi, 50, 9);
+ idle();
PS2_USART_INIT();
PS2_USART_RX_INT_ON();
- res = ps2_host_recv_response();
+ return ps2_host_recv_response();
ERROR:
idle();
PS2_USART_INIT();
PS2_USART_RX_INT_ON();
- return res;
+ return 0;
}
-// Do polling data from keyboard to get response to last command.
uint8_t ps2_host_recv_response(void)
{
- while (!pbuf_has_data()) {
- _delay_ms(1); // without this delay it seems to fall into deadlock
+ // Command may take 25ms/20ms at most([5]p.46, [3]p.21)
+ uint8_t retry = 25;
+ while (retry-- && !pbuf_has_data()) {
+ _delay_ms(1);
}
return pbuf_dequeue();
}
uint8_t ps2_host_recv(void)
{
- return pbuf_dequeue();
+ if (pbuf_has_data()) {
+ ps2_error = PS2_ERR_NONE;
+ return pbuf_dequeue();
+ } else {
+ ps2_error = PS2_ERR_NODATA;
+ return 0;
+ }
}
ISR(PS2_USART_RX_VECT)
{
- uint8_t error = PS2_USART_ERROR;
+ // TODO: request RESEND when error occurs?
+ uint8_t error = PS2_USART_ERROR; // USART error should be read before data
uint8_t data = PS2_USART_RX_DATA;
if (!error) {
pbuf_enqueue(data);
+ } else {
+ xprintf("PS2 USART error: %02X data: %02X\n", error, data);
}
}
/* send LED state to keyboard */
void ps2_host_set_led(uint8_t led)
{
- // send 0xED then keyboard keeps waiting for next LED data
- // and keyboard does not send any scan codes during waiting.
- // If fail to send LED data keyboard looks like being freezed.
- uint8_t retry = 3;
- while (retry-- && ps2_host_send(PS2_SET_LED) != PS2_ACK)
- ;
- retry = 3;
- while (retry-- && ps2_host_send(led) != PS2_ACK)
- ;
-}
-
-
-/*--------------------------------------------------------------------
- * static functions
- *------------------------------------------------------------------*/
-static inline void clock_lo()
-{
- PS2_CLOCK_PORT &= ~(1<<PS2_CLOCK_BIT);
- PS2_CLOCK_DDR |= (1<<PS2_CLOCK_BIT);
-}
-static inline void clock_hi()
-{
- /* input with pull up */
- PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
- PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
-}
-static inline bool clock_in()
-{
- PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
- PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
- _delay_us(1);
- return PS2_CLOCK_PIN&(1<<PS2_CLOCK_BIT);
-}
-static inline void data_lo()
-{
- PS2_DATA_PORT &= ~(1<<PS2_DATA_BIT);
- PS2_DATA_DDR |= (1<<PS2_DATA_BIT);
-}
-static inline void data_hi()
-{
- /* input with pull up */
- PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
- PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
-}
-static inline bool data_in()
-{
- PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
- PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
- _delay_us(1);
- return PS2_DATA_PIN&(1<<PS2_DATA_BIT);
-}
-
-static inline uint16_t wait_clock_lo(uint16_t us)
-{
- while (clock_in() && us) { asm(""); _delay_us(1); us--; }
- return us;
-}
-static inline uint16_t wait_clock_hi(uint16_t us)
-{
- while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
- return us;
-}
-static inline uint16_t wait_data_lo(uint16_t us)
-{
- while (data_in() && us) { asm(""); _delay_us(1); us--; }
- return us;
-}
-static inline uint16_t wait_data_hi(uint16_t us)
-{
- while (!data_in() && us) { asm(""); _delay_us(1); us--; }
- return us;
-}
-
-/* idle state that device can send */
-static inline void idle(void)
-{
- clock_hi();
- data_hi();
-}
-
-/* inhibit device to send */
-static inline void inhibit(void)
-{
- clock_lo();
- data_hi();
+ ps2_host_send(0xED);
+ ps2_host_send(led);
}
pbuf[pbuf_head] = data;
pbuf_head = next;
} else {
- debug("pbuf: full\n");
+ print("pbuf: full\n");
}
SREG = sreg;
}
-
static inline uint8_t pbuf_dequeue(void)
{
uint8_t val = 0;
projects / tmk_firmware.git / blobdiff