You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
367 lines
9.2 KiB
367 lines
9.2 KiB
/*
|
|
* WARNING: be careful changing this code, it is very timing dependent
|
|
*/
|
|
|
|
#ifndef F_CPU
|
|
#define F_CPU 16000000
|
|
#endif
|
|
|
|
#include <avr/io.h>
|
|
#include <avr/interrupt.h>
|
|
#include <util/delay.h>
|
|
#include <stddef.h>
|
|
#include <stdbool.h>
|
|
#include "serial.h"
|
|
//#include <pro_micro.h>
|
|
|
|
#ifdef USE_SERIAL
|
|
|
|
#define ALWAYS_INLINE __attribute__((always_inline))
|
|
#define NO_INLINE __attribute__((noinline))
|
|
#define _delay_sub_us(x) __builtin_avr_delay_cycles(x)
|
|
|
|
// Serial pulse period in microseconds.
|
|
#define SELECT_SERIAL_SPEED 1
|
|
#if SELECT_SERIAL_SPEED == 0
|
|
// Very High speed
|
|
#define SERIAL_DELAY 4 // micro sec
|
|
#define READ_WRITE_START_ADJUST 33 // cycles
|
|
#define READ_WRITE_WIDTH_ADJUST 3 // cycles
|
|
#elif SELECT_SERIAL_SPEED == 1
|
|
// High speed
|
|
#define SERIAL_DELAY 6 // micro sec
|
|
#define READ_WRITE_START_ADJUST 30 // cycles
|
|
#define READ_WRITE_WIDTH_ADJUST 3 // cycles
|
|
#elif SELECT_SERIAL_SPEED == 2
|
|
// Middle speed
|
|
#define SERIAL_DELAY 12 // micro sec
|
|
#define READ_WRITE_START_ADJUST 30 // cycles
|
|
#define READ_WRITE_WIDTH_ADJUST 3 // cycles
|
|
#elif SELECT_SERIAL_SPEED == 3
|
|
// Low speed
|
|
#define SERIAL_DELAY 24 // micro sec
|
|
#define READ_WRITE_START_ADJUST 30 // cycles
|
|
#define READ_WRITE_WIDTH_ADJUST 3 // cycles
|
|
#elif SELECT_SERIAL_SPEED == 4
|
|
// Very Low speed
|
|
#define SERIAL_DELAY 50 // micro sec
|
|
#define READ_WRITE_START_ADJUST 30 // cycles
|
|
#define READ_WRITE_WIDTH_ADJUST 3 // cycles
|
|
#else
|
|
#error Illegal Serial Speed
|
|
#endif
|
|
|
|
|
|
#define SERIAL_DELAY_HALF1 (SERIAL_DELAY/2)
|
|
#define SERIAL_DELAY_HALF2 (SERIAL_DELAY - SERIAL_DELAY/2)
|
|
|
|
#define SLAVE_INT_WIDTH 1
|
|
#define SLAVE_INT_RESPONSE_TIME SERIAL_DELAY
|
|
|
|
static SSTD_t *Transaction_table = NULL;
|
|
|
|
inline static
|
|
void serial_delay(void) {
|
|
_delay_us(SERIAL_DELAY);
|
|
}
|
|
|
|
inline static
|
|
void serial_delay_half1(void) {
|
|
_delay_us(SERIAL_DELAY_HALF1);
|
|
}
|
|
|
|
inline static
|
|
void serial_delay_half2(void) {
|
|
_delay_us(SERIAL_DELAY_HALF2);
|
|
}
|
|
|
|
inline static void serial_output(void) ALWAYS_INLINE;
|
|
inline static
|
|
void serial_output(void) {
|
|
debug_output_mode();
|
|
SERIAL_PIN_DDR |= SERIAL_PIN_MASK;
|
|
}
|
|
|
|
// make the serial pin an input with pull-up resistor
|
|
inline static void serial_input_with_pullup(void) ALWAYS_INLINE;
|
|
inline static
|
|
void serial_input_with_pullup(void) {
|
|
debug_input_mode();
|
|
SERIAL_PIN_DDR &= ~SERIAL_PIN_MASK;
|
|
SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
|
|
}
|
|
|
|
inline static
|
|
uint8_t serial_read_pin(void) {
|
|
return !!(SERIAL_PIN_INPUT & SERIAL_PIN_MASK);
|
|
}
|
|
|
|
inline static void serial_low(void) ALWAYS_INLINE;
|
|
inline static
|
|
void serial_low(void) {
|
|
SERIAL_PIN_PORT &= ~SERIAL_PIN_MASK;
|
|
}
|
|
|
|
inline static void serial_high(void) ALWAYS_INLINE;
|
|
inline static
|
|
void serial_high(void) {
|
|
SERIAL_PIN_PORT |= SERIAL_PIN_MASK;
|
|
}
|
|
|
|
void soft_serial_initiator_init(SSTD_t *sstd_table)
|
|
{
|
|
serial_debug_init();
|
|
Transaction_table = sstd_table;
|
|
serial_output();
|
|
serial_high();
|
|
}
|
|
|
|
void soft_serial_target_init(SSTD_t *sstd_table)
|
|
{
|
|
serial_debug_init();
|
|
Transaction_table = sstd_table;
|
|
serial_input_with_pullup();
|
|
|
|
#if SERIAL_PIN_MASK == _BV(PD0)
|
|
// Enable INT0
|
|
EIMSK |= _BV(INT0);
|
|
// Trigger on falling edge of INT0
|
|
EICRA &= ~(_BV(ISC00) | _BV(ISC01));
|
|
#elif SERIAL_PIN_MASK == _BV(PD2)
|
|
// Enable INT2
|
|
EIMSK |= _BV(INT2);
|
|
// Trigger on falling edge of INT2
|
|
EICRA &= ~(_BV(ISC20) | _BV(ISC21));
|
|
#else
|
|
#error unknown SERIAL_PIN_MASK value
|
|
#endif
|
|
}
|
|
|
|
// Used by the sender to synchronize timing with the reciver.
|
|
static void sync_recv(void) NO_INLINE;
|
|
static
|
|
void sync_recv(void) {
|
|
debug_sync_start();
|
|
for (uint8_t i = 0; i < SERIAL_DELAY*5 && serial_read_pin(); i++ ) {
|
|
debug_sync_end(); debug_sync_start();
|
|
}
|
|
// This shouldn't hang if the target disconnects because the
|
|
// serial line will float to high if the target does disconnect.
|
|
while (!serial_read_pin());
|
|
debug_sync_end();
|
|
}
|
|
|
|
// Used by the reciver to send a synchronization signal to the sender.
|
|
static void sync_send(void)NO_INLINE;
|
|
static
|
|
void sync_send(void) {
|
|
debug_sync_start();
|
|
serial_low();
|
|
serial_delay();
|
|
serial_high();
|
|
debug_sync_end();
|
|
}
|
|
|
|
// Reads a byte from the serial line
|
|
static uint8_t serial_read_chunk(uint8_t *pterrcount, uint8_t bit) NO_INLINE;
|
|
static uint8_t serial_read_chunk(uint8_t *pterrcount, uint8_t bit) {
|
|
uint8_t byte, i, p, pb;
|
|
|
|
_delay_sub_us(READ_WRITE_START_ADJUST);
|
|
for( i = 0, byte = 0, p = 0; i < bit; i++ ) {
|
|
serial_delay_half1(); // read the middle of pulses
|
|
debug_recvsample();
|
|
if( serial_read_pin() ) {
|
|
byte = (byte << 1) | 1; p ^= 1;
|
|
} else {
|
|
byte = (byte << 1) | 0; p ^= 0;
|
|
}
|
|
debug_recvsample();
|
|
_delay_sub_us(READ_WRITE_WIDTH_ADJUST);
|
|
serial_delay_half2();
|
|
debug_dummy_delay_recv();
|
|
}
|
|
/* recive parity bit */
|
|
serial_delay_half1(); // read the middle of pulses
|
|
debug_recvsample();
|
|
pb = serial_read_pin();
|
|
debug_recvsample();
|
|
_delay_sub_us(READ_WRITE_WIDTH_ADJUST);
|
|
serial_delay_half2();
|
|
debug_dummy_delay_recv();
|
|
|
|
if( p == pb ) debug_parity_on();
|
|
*pterrcount += (p != pb)? 1 : 0;
|
|
debug_parity_off();
|
|
|
|
return byte;
|
|
}
|
|
|
|
// Sends a byte with MSB ordering
|
|
void serial_write_chunk(uint8_t data, uint8_t bit) NO_INLINE;
|
|
void serial_write_chunk(uint8_t data, uint8_t bit) {
|
|
uint8_t b, p;
|
|
for( p = 0, b = 1<<(bit-1); b ; b >>= 1) {
|
|
if(data & b) {
|
|
serial_high(); p ^= 1;
|
|
} else {
|
|
serial_low(); p ^= 0;
|
|
}
|
|
debug_recvsample();
|
|
serial_delay();
|
|
debug_recvsample();
|
|
debug_dummy_delay_send();
|
|
}
|
|
/* send parity bit */
|
|
if(p & 1) { serial_high(); }
|
|
else { serial_low(); }
|
|
debug_recvsample();
|
|
serial_delay();
|
|
debug_recvsample();
|
|
debug_dummy_delay_send();
|
|
|
|
serial_low(); // sync_send() / senc_recv() need raise edge
|
|
}
|
|
|
|
static void serial_send_packet(uint8_t *buffer, uint8_t size) NO_INLINE;
|
|
static
|
|
void serial_send_packet(uint8_t *buffer, uint8_t size) {
|
|
for (uint8_t i = 0; i < size; ++i) {
|
|
uint8_t data;
|
|
data = buffer[i];
|
|
sync_send();
|
|
debug_bytewidth_start();
|
|
serial_write_chunk(data,8);
|
|
debug_bytewidth_end();
|
|
}
|
|
}
|
|
|
|
static uint8_t serial_recive_packet(uint8_t *buffer, uint8_t size) NO_INLINE;
|
|
static
|
|
uint8_t serial_recive_packet(uint8_t *buffer, uint8_t size) {
|
|
uint8_t pecount = 0;
|
|
for (uint8_t i = 0; i < size; ++i) {
|
|
uint8_t data;
|
|
sync_recv();
|
|
debug_bytewidth_start();
|
|
data = serial_read_chunk(&pecount, 8);
|
|
debug_bytewidth_end();
|
|
buffer[i] = data;
|
|
}
|
|
return pecount == 0;
|
|
}
|
|
|
|
inline static
|
|
void change_sender2reciver(void) {
|
|
sync_send(); //0
|
|
serial_delay_half1(); //1
|
|
serial_low(); //2
|
|
serial_input_with_pullup(); //2
|
|
serial_delay_half1(); //3
|
|
}
|
|
|
|
inline static
|
|
void change_reciver2sender(void) {
|
|
sync_recv(); //0
|
|
serial_delay(); //1
|
|
serial_low(); //3
|
|
serial_output(); //3
|
|
serial_delay_half1(); //4
|
|
}
|
|
|
|
// interrupt handle to be used by the target device
|
|
ISR(SERIAL_PIN_INTERRUPT) {
|
|
debug_output_mode(); debug_input_mode(); // indicate intterupt entry
|
|
|
|
serial_low();
|
|
serial_output();
|
|
SSTD_t *trans = Transaction_table;
|
|
|
|
// target send phase
|
|
if( trans->target2initiator_buffer_size > 0 )
|
|
serial_send_packet((uint8_t *)trans->target2initiator_buffer,
|
|
trans->target2initiator_buffer_size);
|
|
// target switch to input
|
|
change_sender2reciver();
|
|
|
|
// target recive phase
|
|
if( trans->initiator2target_buffer_size > 0 ) {
|
|
if (serial_recive_packet((uint8_t *)trans->initiator2target_buffer,
|
|
trans->initiator2target_buffer_size) ) {
|
|
*trans->status = RECIVE_ACCEPTED;
|
|
} else {
|
|
debug_parity_on();
|
|
*trans->status = RECIVE_DATA_ERROR;
|
|
debug_parity_off();
|
|
}
|
|
}
|
|
|
|
sync_recv(); //weit initiator output to high
|
|
debug_output_mode(); debug_input_mode(); // indicate intterupt exit
|
|
}
|
|
|
|
/////////
|
|
// start transaction by initiator
|
|
//
|
|
// int soft_serial_transaction(int sstd_index)
|
|
//
|
|
// Returns:
|
|
// TRANSACTION_END
|
|
// TRANSACTION_NO_RESPONSE
|
|
// TRANSACTION_DATA_ERROR
|
|
int soft_serial_transaction(int sstd_index) {
|
|
// this code is very time dependent, so we need to disable interrupts
|
|
SSTD_t *trans = &Transaction_table[sstd_index];
|
|
cli();
|
|
|
|
// signal to the target that we want to start a transaction
|
|
serial_output();
|
|
serial_low();
|
|
_delay_us(SLAVE_INT_WIDTH);
|
|
|
|
// wait for the target response
|
|
serial_input_with_pullup();
|
|
_delay_us(SLAVE_INT_RESPONSE_TIME);
|
|
|
|
// check if the target is present
|
|
if (serial_read_pin()) {
|
|
// target failed to pull the line low, assume not present
|
|
serial_output();
|
|
serial_high();
|
|
sei();
|
|
return TRANSACTION_NO_RESPONSE;
|
|
}
|
|
|
|
// initiator recive phase
|
|
// if the target is present syncronize with it
|
|
if( trans->target2initiator_buffer_size > 0 ) {
|
|
if (!serial_recive_packet((uint8_t *)trans->target2initiator_buffer,
|
|
trans->target2initiator_buffer_size) ) {
|
|
debug_parity_on();
|
|
serial_output();
|
|
serial_high();
|
|
debug_parity_off();
|
|
sei();
|
|
return TRANSACTION_DATA_ERROR;
|
|
}
|
|
}
|
|
|
|
// initiator switch to output
|
|
change_reciver2sender();
|
|
|
|
// initiator send phase
|
|
if( trans->initiator2target_buffer_size > 0 ) {
|
|
serial_send_packet((uint8_t *)trans->initiator2target_buffer,
|
|
trans->initiator2target_buffer_size);
|
|
}
|
|
|
|
// always, release the line when not in use
|
|
sync_send();
|
|
debug_input_mode(); debug_output_mode(); // indicate intterupt exit
|
|
|
|
sei();
|
|
return TRANSACTION_END;
|
|
}
|
|
|
|
#endif
|