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qmk_firmware/keyboards/helix/serial.c

445 lines
11 KiB
C
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/*
* 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
#ifndef SERIAL_USE_MULTI_TRANSACTION
/* --- USE Simple API (OLD API, compatible with let's split serial.c) */
#if SERIAL_SLAVE_BUFFER_LENGTH > 0
uint8_t volatile serial_slave_buffer[SERIAL_SLAVE_BUFFER_LENGTH] = {0};
#endif
#if SERIAL_MASTER_BUFFER_LENGTH > 0
uint8_t volatile serial_master_buffer[SERIAL_MASTER_BUFFER_LENGTH] = {0};
#endif
uint8_t volatile status0 = 0;
SSTD_t transactions[] = {
{ (uint8_t *)&status0,
#if SERIAL_MASTER_BUFFER_LENGTH > 0
sizeof(serial_master_buffer), (uint8_t *)serial_master_buffer,
#else
0, (uint8_t *)NULL,
#endif
#if SERIAL_SLAVE_BUFFER_LENGTH > 0
sizeof(serial_slave_buffer), (uint8_t *)serial_slave_buffer
#else
0, (uint8_t *)NULL,
#endif
}
};
void serial_master_init(void)
{ soft_serial_initiator_init(transactions); }
void serial_slave_init(void)
{ soft_serial_target_init(transactions); }
// 0 => no error
// 1 => slave did not respond
// 2 => checksum error
int serial_update_buffers()
{ return soft_serial_transaction(); }
#endif // Simple API (OLD API, compatible with let's split serial.c)
#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 TID_SEND_ADJUST 14
#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_US 1
#ifndef SERIAL_USE_MULTI_TRANSACTION
#define SLAVE_INT_RESPONSE_TIME SERIAL_DELAY
#else
#define SLAVE_INT_ACK_WIDTH_UNIT 2
#define SLAVE_INT_ACK_WIDTH 4
#endif
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) {
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) {
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)
{
Transaction_table = sstd_table;
serial_output();
serial_high();
}
void soft_serial_target_init(SSTD_t *sstd_table)
{
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) {
for (uint8_t i = 0; i < SERIAL_DELAY*5 && serial_read_pin(); i++ ) {
}
// 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());
}
// Used by the reciver to send a synchronization signal to the sender.
static void sync_send(void)NO_INLINE;
static
void sync_send(void) {
serial_low();
serial_delay();
serial_high();
}
// 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
if( serial_read_pin() ) {
byte = (byte << 1) | 1; p ^= 1;
} else {
byte = (byte << 1) | 0; p ^= 0;
}
_delay_sub_us(READ_WRITE_WIDTH_ADJUST);
serial_delay_half2();
}
/* recive parity bit */
serial_delay_half1(); // read the middle of pulses
pb = serial_read_pin();
_delay_sub_us(READ_WRITE_WIDTH_ADJUST);
serial_delay_half2();
*pterrcount += (p != pb)? 1 : 0;
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;
}
serial_delay();
}
/* send parity bit */
if(p & 1) { serial_high(); }
else { serial_low(); }
serial_delay();
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();
serial_write_chunk(data,8);
}
}
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();
data = serial_read_chunk(&pecount, 8);
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) {
#ifndef SERIAL_USE_MULTI_TRANSACTION
serial_low();
serial_output();
SSTD_t *trans = Transaction_table;
#else
// recive transaction table index
uint8_t tid;
uint8_t pecount = 0;
sync_recv();
tid = serial_read_chunk(&pecount,4);
if(pecount> 0)
return;
serial_delay_half1();
serial_high(); // response step1 low->high
serial_output();
_delay_sub_us(SLAVE_INT_ACK_WIDTH_UNIT*SLAVE_INT_ACK_WIDTH);
SSTD_t *trans = &Transaction_table[tid];
serial_low(); // response step2 ack high->low
#endif
// 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 = TRANSACTION_ACCEPTED;
} else {
*trans->status = TRANSACTION_DATA_ERROR;
}
} else {
*trans->status = TRANSACTION_ACCEPTED;
}
sync_recv(); //weit initiator output to high
}
/////////
// start transaction by initiator
//
// int soft_serial_transaction(int sstd_index)
//
// Returns:
// TRANSACTION_END
// TRANSACTION_NO_RESPONSE
// TRANSACTION_DATA_ERROR
// this code is very time dependent, so we need to disable interrupts
#ifndef SERIAL_USE_MULTI_TRANSACTION
int soft_serial_transaction(void) {
SSTD_t *trans = Transaction_table;
#else
int soft_serial_transaction(int sstd_index) {
SSTD_t *trans = &Transaction_table[sstd_index];
#endif
cli();
// signal to the target that we want to start a transaction
serial_output();
serial_low();
_delay_us(SLAVE_INT_WIDTH_US);
#ifndef SERIAL_USE_MULTI_TRANSACTION
// 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();
*trans->status = TRANSACTION_NO_RESPONSE;
sei();
return TRANSACTION_NO_RESPONSE;
}
#else
// send transaction table index
sync_send();
_delay_sub_us(TID_SEND_ADJUST);
serial_write_chunk(sstd_index, 4);
serial_delay_half1();
// wait for the target response (step1 low->high)
serial_input_with_pullup();
while( !serial_read_pin() ) {
_delay_sub_us(2);
}
// check if the target is present (step2 high->low)
for( int i = 0; serial_read_pin(); i++ ) {
if (i > SLAVE_INT_ACK_WIDTH + 1) {
// slave failed to pull the line low, assume not present
serial_output();
serial_high();
*trans->status = TRANSACTION_NO_RESPONSE;
sei();
return TRANSACTION_NO_RESPONSE;
}
_delay_sub_us(SLAVE_INT_ACK_WIDTH_UNIT);
}
#endif
// 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) ) {
serial_output();
serial_high();
*trans->status = TRANSACTION_DATA_ERROR;
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();
*trans->status = TRANSACTION_END;
sei();
return TRANSACTION_END;
}
#ifdef SERIAL_USE_MULTI_TRANSACTION
int soft_serial_get_and_clean_status(int sstd_index) {
SSTD_t *trans = &Transaction_table[sstd_index];
cli();
int retval = *trans->status;
*trans->status = 0;;
sei();
return retval;
}
#endif
#endif
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