/* * 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(); *trans->status = (checksum_computed == checksum_received) ? TRANSACTION_ACCEPTED : TRANSACTION_DATA_ERROR; // end transaction serial_input(); // TODO: remove extra delay between transactions serial_delay(); chSysUnlockFromISR(); } ///////// // 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 int soft_serial_transaction(int sstd_index) { if (sstd_index > NUM_TOTAL_TRANSACTIONS) return TRANSACTION_TYPE_ERROR; split_transaction_desc_t *trans = &split_transaction_table[sstd_index]; if (!trans->status) return TRANSACTION_TYPE_ERROR; // not registered // 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 TRANSACTION_NO_RESPONSE; } // 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 TRANSACTION_DATA_ERROR; } // always, release the line when not in use serial_high(); serial_output(); chSysUnlock(); return TRANSACTION_END; }