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qmk_firmware/platforms/avr/drivers/serial.c

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/*
* WARNING: be careful changing this code, it is very timing dependent
*
* 2018-10-28 checked
* avr-gcc 4.9.2
* avr-gcc 5.4.0
* avr-gcc 7.3.0
*/
#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 "gpio.h"
#include "serial.h"
#ifdef SOFT_SERIAL_PIN
# if !(defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) || defined(__AVR_AT90USB162__) || defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__))
# error serial.c is not supported for the currently selected MCU
# endif
// if using ATmega32U4/2, AT90USBxxx I2C, can not use PD0 and PD1 in soft serial.
# if defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
# if defined(USE_AVR_I2C) && (SOFT_SERIAL_PIN == D0 || SOFT_SERIAL_PIN == D1)
# error Using I2C, so can not use PD0, PD1
# endif
# endif
// PD0..PD3, common config
# if SOFT_SERIAL_PIN == D0
# define EIMSK_BIT _BV(INT0)
# define EICRx_BIT (~(_BV(ISC00) | _BV(ISC01)))
# define SERIAL_PIN_INTERRUPT INT0_vect
# define EICRx EICRA
# elif SOFT_SERIAL_PIN == D1
# define EIMSK_BIT _BV(INT1)
# define EICRx_BIT (~(_BV(ISC10) | _BV(ISC11)))
# define SERIAL_PIN_INTERRUPT INT1_vect
# define EICRx EICRA
# elif SOFT_SERIAL_PIN == D2
# define EIMSK_BIT _BV(INT2)
# define EICRx_BIT (~(_BV(ISC20) | _BV(ISC21)))
# define SERIAL_PIN_INTERRUPT INT2_vect
# define EICRx EICRA
# elif SOFT_SERIAL_PIN == D3
# define EIMSK_BIT _BV(INT3)
# define EICRx_BIT (~(_BV(ISC30) | _BV(ISC31)))
# define SERIAL_PIN_INTERRUPT INT3_vect
# define EICRx EICRA
# endif
// ATmegaxxU2/AT90USB162 specific config
# if defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_AT90USB162__)
// PD4(INT5), PD6(INT6), PD7(INT7), PC7(INT4)
# if SOFT_SERIAL_PIN == D4
# define EIMSK_BIT _BV(INT5)
# define EICRx_BIT (~(_BV(ISC50) | _BV(ISC51)))
# define SERIAL_PIN_INTERRUPT INT5_vect
# define EICRx EICRB
# elif SOFT_SERIAL_PIN == D6
# define EIMSK_BIT _BV(INT6)
# define EICRx_BIT (~(_BV(ISC60) | _BV(ISC61)))
# define SERIAL_PIN_INTERRUPT INT6_vect
# define EICRx EICRB
# elif SOFT_SERIAL_PIN == D7
# define EIMSK_BIT _BV(INT7)
# define EICRx_BIT (~(_BV(ISC70) | _BV(ISC71)))
# define SERIAL_PIN_INTERRUPT INT7_vect
# define EICRx EICRB
# elif SOFT_SERIAL_PIN == C7
# define EIMSK_BIT _BV(INT4)
# define EICRx_BIT (~(_BV(ISC40) | _BV(ISC41)))
# define SERIAL_PIN_INTERRUPT INT4_vect
# define EICRx EICRB
# endif
# endif
// ATmegaxxU4 specific config
# if defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__)
// PE6(INT6)
# if SOFT_SERIAL_PIN == E6
# define EIMSK_BIT _BV(INT6)
# define EICRx_BIT (~(_BV(ISC60) | _BV(ISC61)))
# define SERIAL_PIN_INTERRUPT INT6_vect
# define EICRx EICRB
# endif
# endif
// AT90USBxxx specific config
# if defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__)
// PE4..PE7(INT4..INT7)
# if SOFT_SERIAL_PIN == E4
# define EIMSK_BIT _BV(INT4)
# define EICRx_BIT (~(_BV(ISC40) | _BV(ISC41)))
# define SERIAL_PIN_INTERRUPT INT4_vect
# define EICRx EICRB
# elif SOFT_SERIAL_PIN == E5
# define EIMSK_BIT _BV(INT5)
# define EICRx_BIT (~(_BV(ISC50) | _BV(ISC51)))
# define SERIAL_PIN_INTERRUPT INT5_vect
# define EICRx EICRB
# elif SOFT_SERIAL_PIN == E6
# define EIMSK_BIT _BV(INT6)
# define EICRx_BIT (~(_BV(ISC60) | _BV(ISC61)))
# define SERIAL_PIN_INTERRUPT INT6_vect
# define EICRx EICRB
# elif SOFT_SERIAL_PIN == E7
# define EIMSK_BIT _BV(INT7)
# define EICRx_BIT (~(_BV(ISC70) | _BV(ISC71)))
# define SERIAL_PIN_INTERRUPT INT7_vect
# define EICRx EICRB
# endif
# endif
# ifndef SERIAL_PIN_INTERRUPT
# error invalid SOFT_SERIAL_PIN value
# endif
# define ALWAYS_INLINE __attribute__((always_inline))
# define NO_INLINE __attribute__((noinline))
# define _delay_sub_us(x) __builtin_avr_delay_cycles(x)
// parity check
# define ODD_PARITY 1
# define EVEN_PARITY 0
# define PARITY EVEN_PARITY
# ifdef SERIAL_DELAY
// custom setup in config.h
// #define TID_SEND_ADJUST 2
// #define SERIAL_DELAY 6 // micro sec
// #define READ_WRITE_START_ADJUST 30 // cycles
// #define READ_WRITE_WIDTH_ADJUST 8 // cycles
# else
// ============ Standard setups ============
# ifndef SELECT_SOFT_SERIAL_SPEED
# define SELECT_SOFT_SERIAL_SPEED 1
// 0: about 189kbps (Experimental only)
// 1: about 137kbps (default)
// 2: about 75kbps
// 3: about 39kbps
// 4: about 26kbps
// 5: about 20kbps
# endif
# if __GNUC__ < 6
# define TID_SEND_ADJUST 14
# else
# define TID_SEND_ADJUST 2
# endif
# if SELECT_SOFT_SERIAL_SPEED == 0
// Very High speed
# define SERIAL_DELAY 4 // micro sec
# if __GNUC__ < 6
# define READ_WRITE_START_ADJUST 33 // cycles
# define READ_WRITE_WIDTH_ADJUST 3 // cycles
# else
# define READ_WRITE_START_ADJUST 34 // cycles
# define READ_WRITE_WIDTH_ADJUST 7 // cycles
# endif
# elif SELECT_SOFT_SERIAL_SPEED == 1
// High speed
# define SERIAL_DELAY 6 // micro sec
# if __GNUC__ < 6
# define READ_WRITE_START_ADJUST 30 // cycles
# define READ_WRITE_WIDTH_ADJUST 3 // cycles
# else
# define READ_WRITE_START_ADJUST 33 // cycles
# define READ_WRITE_WIDTH_ADJUST 7 // cycles
# endif
# elif SELECT_SOFT_SERIAL_SPEED == 2
// Middle speed
# define SERIAL_DELAY 12 // micro sec
# define READ_WRITE_START_ADJUST 30 // cycles
# if __GNUC__ < 6
# define READ_WRITE_WIDTH_ADJUST 3 // cycles
# else
# define READ_WRITE_WIDTH_ADJUST 7 // cycles
# endif
# elif SELECT_SOFT_SERIAL_SPEED == 3
// Low speed
# define SERIAL_DELAY 24 // micro sec
# define READ_WRITE_START_ADJUST 30 // cycles
# if __GNUC__ < 6
# define READ_WRITE_WIDTH_ADJUST 3 // cycles
# else
# define READ_WRITE_WIDTH_ADJUST 7 // cycles
# endif
# elif SELECT_SOFT_SERIAL_SPEED == 4
// Very Low speed
# define SERIAL_DELAY 36 // micro sec
# define READ_WRITE_START_ADJUST 30 // cycles
# if __GNUC__ < 6
# define READ_WRITE_WIDTH_ADJUST 3 // cycles
# else
# define READ_WRITE_WIDTH_ADJUST 7 // cycles
# endif
# elif SELECT_SOFT_SERIAL_SPEED == 5
// Ultra Low speed
# define SERIAL_DELAY 48 // micro sec
# define READ_WRITE_START_ADJUST 30 // cycles
# if __GNUC__ < 6
# define READ_WRITE_WIDTH_ADJUST 3 // cycles
# else
# define READ_WRITE_WIDTH_ADJUST 7 // cycles
# endif
# else
# error invalid SELECT_SOFT_SERIAL_SPEED value
# endif /* SELECT_SOFT_SERIAL_SPEED */
# endif /* SERIAL_DELAY */
# define SERIAL_DELAY_HALF1 (SERIAL_DELAY / 2)
# define SERIAL_DELAY_HALF2 (SERIAL_DELAY - SERIAL_DELAY / 2)
# define SLAVE_INT_WIDTH_US 1
# define SLAVE_INT_ACK_WIDTH_UNIT 2
# define SLAVE_INT_ACK_WIDTH 4
inline static void serial_delay(void) ALWAYS_INLINE;
inline static void serial_delay(void) {
_delay_us(SERIAL_DELAY);
}
inline static void serial_delay_half1(void) ALWAYS_INLINE;
inline static void serial_delay_half1(void) {
_delay_us(SERIAL_DELAY_HALF1);
}
inline static void serial_delay_half2(void) ALWAYS_INLINE;
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) {
setPinOutput(SOFT_SERIAL_PIN);
}
// 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) {
setPinInputHigh(SOFT_SERIAL_PIN);
}
inline static uint8_t serial_read_pin(void) ALWAYS_INLINE;
inline static uint8_t serial_read_pin(void) {
return !!readPin(SOFT_SERIAL_PIN);
}
inline static void serial_low(void) ALWAYS_INLINE;
inline static void serial_low(void) {
writePinLow(SOFT_SERIAL_PIN);
}
inline static void serial_high(void) ALWAYS_INLINE;
inline static void serial_high(void) {
writePinHigh(SOFT_SERIAL_PIN);
}
void soft_serial_initiator_init(void) {
serial_output();
serial_high();
}
void soft_serial_target_init(void) {
serial_input_with_pullup();
// Enable INT0-INT7
EIMSK |= EIMSK_BIT;
EICRx &= EICRx_BIT;
}
// 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 = PARITY; 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 = PARITY, 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
}
static inline uint8_t nibble_bits_count(uint8_t bits) {
bits = (bits & 0x5) + (bits >> 1 & 0x5);
bits = (bits & 0x3) + (bits >> 2 & 0x3);
return bits;
}
// interrupt handle to be used by the target device
ISR(SERIAL_PIN_INTERRUPT) {
// recive transaction table index
uint8_t tid, bits;
uint8_t pecount = 0;
sync_recv();
bits = serial_read_chunk(&pecount, 8);
tid = bits >> 3;
bits = (bits & 7) != (nibble_bits_count(tid) & 7);
if (bits || pecount > 0 || tid > NUM_TOTAL_TRANSACTIONS) {
return;
}
serial_delay_half1();
serial_high(); // response step1 low->high
serial_output();
_delay_sub_us(SLAVE_INT_ACK_WIDTH_UNIT * SLAVE_INT_ACK_WIDTH);
split_transaction_desc_t *trans = &split_transaction_table[tid];
serial_low(); // response step2 ack high->low
// If the transaction has a callback, we can execute it now
if (trans->slave_callback) {
trans->slave_callback(trans->initiator2target_buffer_size, split_trans_initiator2target_buffer(trans), trans->target2initiator_buffer_size, split_trans_target2initiator_buffer(trans));
}
// target send phase
if (trans->target2initiator_buffer_size > 0) serial_send_packet((uint8_t *)split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size);
// target switch to input
change_sender2reciver();
// target recive phase
if (trans->initiator2target_buffer_size > 0) {
serial_recive_packet((uint8_t *)split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size);
}
sync_recv(); // weit initiator output to high
}
/////////
// start transaction by initiator
//
// bool soft_serial_transaction(int sstd_index)
//
// this code is very time dependent, so we need to disable interrupts
bool soft_serial_transaction(int sstd_index) {
if (sstd_index > NUM_TOTAL_TRANSACTIONS) return false;
split_transaction_desc_t *trans = &split_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_US);
// send transaction table index
int tid = (sstd_index << 3) | (7 & nibble_bits_count(sstd_index));
sync_send();
_delay_sub_us(TID_SEND_ADJUST);
serial_write_chunk(tid, 8);
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();
sei();
return false;
}
_delay_sub_us(SLAVE_INT_ACK_WIDTH_UNIT);
}
// initiator recive phase
// if the target is present syncronize with it
if (trans->target2initiator_buffer_size > 0) {
if (!serial_recive_packet((uint8_t *)split_trans_target2initiator_buffer(trans), trans->target2initiator_buffer_size)) {
serial_output();
serial_high();
sei();
return false;
}
}
// initiator switch to output
change_reciver2sender();
// initiator send phase
if (trans->initiator2target_buffer_size > 0) {
serial_send_packet((uint8_t *)split_trans_initiator2target_buffer(trans), trans->initiator2target_buffer_size);
}
// always, release the line when not in use
sync_send();
sei();
return true;
}
#endif
// Helix serial.c history
// 2018-1-29 fork from let's split and add PD2, modify sync_recv() (#2308, bceffdefc)
// 2018-6-28 bug fix master to slave comm and speed up (#3255, 1038bbef4)
// (adjusted with avr-gcc 4.9.2)
// 2018-7-13 remove USE_SERIAL_PD2 macro (#3374, f30d6dd78)
// (adjusted with avr-gcc 4.9.2)
// 2018-8-11 add support multi-type transaction (#3608, feb5e4aae)
// (adjusted with avr-gcc 4.9.2)
// 2018-10-21 fix serial and RGB animation conflict (#4191, 4665e4fff)
// (adjusted with avr-gcc 7.3.0)
// 2018-10-28 re-adjust compiler depend value of delay (#4269, 8517f8a66)
// (adjusted with avr-gcc 5.4.0, 7.3.0)
// 2018-12-17 copy to TOP/quantum/split_common/ and remove backward compatibility code (#4669)
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