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- /*
- * WARNING: be careful changing this code, it is very timing dependent
- */
-
- #include "quantum.h"
- #include "serial.h"
- #include "wait.h"
-
- #include <hal.h>
-
- // TODO: resolve/remove build warnings
- #if defined(RGBLIGHT_ENABLE) && defined(RGBLED_SPLIT) && defined(PROTOCOL_CHIBIOS) && defined(WS2812_DRIVER_BITBANG)
- # warning "RGBLED_SPLIT not supported with bitbang WS2812 driver"
- #endif
-
- // default wait implementation cannot be called within interrupt
- // this method seems to be more accurate than GPT timers
- #if PORT_SUPPORTS_RT == FALSE
- # error "chSysPolledDelayX method not supported on this platform"
- #else
- # undef wait_us
- # define wait_us(x) chSysPolledDelayX(US2RTC(CPU_CLOCK, x))
- #endif
-
- #ifndef SELECT_SOFT_SERIAL_SPEED
- # define SELECT_SOFT_SERIAL_SPEED 1
- // TODO: correct speeds...
- // 0: about 189kbps (Experimental only)
- // 1: about 137kbps (default)
- // 2: about 75kbps
- // 3: about 39kbps
- // 4: about 26kbps
- // 5: about 20kbps
- #endif
-
- // Serial pulse period in microseconds. At the moment, going lower than 12 causes communication failure
- #if SELECT_SOFT_SERIAL_SPEED == 0
- # define SERIAL_DELAY 12
- #elif SELECT_SOFT_SERIAL_SPEED == 1
- # define SERIAL_DELAY 16
- #elif SELECT_SOFT_SERIAL_SPEED == 2
- # define SERIAL_DELAY 24
- #elif SELECT_SOFT_SERIAL_SPEED == 3
- # define SERIAL_DELAY 32
- #elif SELECT_SOFT_SERIAL_SPEED == 4
- # define SERIAL_DELAY 48
- #elif SELECT_SOFT_SERIAL_SPEED == 5
- # define SERIAL_DELAY 64
- #else
- # error invalid SELECT_SOFT_SERIAL_SPEED value
- #endif
-
- inline static void serial_delay(void) {
- wait_us(SERIAL_DELAY);
- }
- inline static void serial_delay_half(void) {
- wait_us(SERIAL_DELAY / 2);
- }
- inline static void serial_delay_blip(void) {
- wait_us(1);
- }
- inline static void serial_output(void) {
- setPinOutput(SOFT_SERIAL_PIN);
- }
- inline static void serial_input(void) {
- setPinInputHigh(SOFT_SERIAL_PIN);
- }
- inline static bool serial_read_pin(void) {
- return !!readPin(SOFT_SERIAL_PIN);
- }
- inline static void serial_low(void) {
- writePinLow(SOFT_SERIAL_PIN);
- }
- inline static void serial_high(void) {
- writePinHigh(SOFT_SERIAL_PIN);
- }
-
- void interrupt_handler(void *arg);
-
- // Use thread + palWaitLineTimeout instead of palSetLineCallback
- // - Methods like setPinOutput and palEnableLineEvent/palDisableLineEvent
- // cause the interrupt to lock up, which would limit to only receiving data...
- static THD_WORKING_AREA(waThread1, 128);
- static THD_FUNCTION(Thread1, arg) {
- (void)arg;
- chRegSetThreadName("blinker");
- while (true) {
- palWaitLineTimeout(SOFT_SERIAL_PIN, TIME_INFINITE);
- interrupt_handler(NULL);
- }
- }
-
- void soft_serial_initiator_init(void) {
- serial_output();
- serial_high();
- }
-
- void soft_serial_target_init(void) {
- serial_input();
-
- palEnablePadEvent(PAL_PORT(SOFT_SERIAL_PIN), PAL_PAD(SOFT_SERIAL_PIN), PAL_EVENT_MODE_FALLING_EDGE);
- chThdCreateStatic(waThread1, sizeof(waThread1), HIGHPRIO, Thread1, NULL);
- }
-
- // Used by the master to synchronize timing with the slave.
- static void __attribute__((noinline)) sync_recv(void) {
- serial_input();
- // This shouldn't hang if the slave disconnects because the
- // serial line will float to high if the slave does disconnect.
- while (!serial_read_pin()) {
- }
-
- serial_delay();
- }
-
- // Used by the slave to send a synchronization signal to the master.
- static void __attribute__((noinline)) sync_send(void) {
- serial_output();
-
- serial_low();
- serial_delay();
-
- serial_high();
- }
-
- // Reads a byte from the serial line
- static uint8_t __attribute__((noinline)) serial_read_byte(void) {
- uint8_t byte = 0;
- serial_input();
- for (uint8_t i = 0; i < 8; ++i) {
- byte = (byte << 1) | serial_read_pin();
- serial_delay();
- }
-
- return byte;
- }
-
- // Sends a byte with MSB ordering
- static void __attribute__((noinline)) serial_write_byte(uint8_t data) {
- uint8_t b = 8;
- serial_output();
- while (b--) {
- if (data & (1 << b)) {
- serial_high();
- } else {
- serial_low();
- }
- serial_delay();
- }
- }
-
- // interrupt handle to be used by the slave device
- void interrupt_handler(void *arg) {
- chSysLockFromISR();
-
- sync_send();
-
- // read mid pulses
- serial_delay_blip();
-
- uint8_t checksum_computed = 0;
- int sstd_index = 0;
-
- sstd_index = serial_read_byte();
- sync_send();
-
- split_transaction_desc_t *trans = &split_transaction_table[sstd_index];
- for (int i = 0; i < trans->initiator2target_buffer_size; ++i) {
- split_trans_initiator2target_buffer(trans)[i] = serial_read_byte();
- sync_send();
- checksum_computed += split_trans_initiator2target_buffer(trans)[i];
- }
- checksum_computed ^= 7;
- uint8_t checksum_received = serial_read_byte();
- sync_send();
-
- // wait for the sync to finish sending
- serial_delay();
-
- // Allow any slave processing to occur
- 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));
- }
-
- uint8_t checksum = 0;
- for (int i = 0; i < trans->target2initiator_buffer_size; ++i) {
- serial_write_byte(split_trans_target2initiator_buffer(trans)[i]);
- sync_send();
- serial_delay_half();
- checksum += split_trans_target2initiator_buffer(trans)[i];
- }
- serial_write_byte(checksum ^ 7);
- sync_send();
-
- // wait for the sync to finish sending
- serial_delay();
-
- // end transaction
- serial_input();
-
- // TODO: remove extra delay between transactions
- serial_delay();
-
- chSysUnlockFromISR();
- }
-
- /////////
- // 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];
-
- // TODO: remove extra delay between transactions
- serial_delay();
-
- // this code is very time dependent, so we need to disable interrupts
- chSysLock();
-
- // signal to the slave that we want to start a transaction
- serial_output();
- serial_low();
- serial_delay_blip();
-
- // wait for the slaves response
- serial_input();
- serial_high();
- serial_delay();
-
- // check if the slave is present
- if (serial_read_pin()) {
- // slave failed to pull the line low, assume not present
- dprintf("serial::NO_RESPONSE\n");
- chSysUnlock();
- return false;
- }
-
- // if the slave is present syncronize with it
-
- uint8_t checksum = 0;
- // send data to the slave
- serial_write_byte(sstd_index); // first chunk is transaction id
- sync_recv();
-
- for (int i = 0; i < trans->initiator2target_buffer_size; ++i) {
- serial_write_byte(split_trans_initiator2target_buffer(trans)[i]);
- sync_recv();
- checksum += split_trans_initiator2target_buffer(trans)[i];
- }
- serial_write_byte(checksum ^ 7);
- sync_recv();
-
- serial_delay();
- serial_delay(); // read mid pulses
-
- // receive data from the slave
- uint8_t checksum_computed = 0;
- for (int i = 0; i < trans->target2initiator_buffer_size; ++i) {
- split_trans_target2initiator_buffer(trans)[i] = serial_read_byte();
- sync_recv();
- checksum_computed += split_trans_target2initiator_buffer(trans)[i];
- }
- checksum_computed ^= 7;
- uint8_t checksum_received = serial_read_byte();
-
- sync_recv();
- serial_delay();
-
- if ((checksum_computed) != (checksum_received)) {
- dprintf("serial::FAIL[%u,%u,%u]\n", checksum_computed, checksum_received, sstd_index);
- serial_output();
- serial_high();
-
- chSysUnlock();
- return false;
- }
-
- // always, release the line when not in use
- serial_high();
- serial_output();
-
- chSysUnlock();
- return true;
- }
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