diff options
Diffstat (limited to 'platforms/chibios/drivers/serial.c')
| -rw-r--r-- | platforms/chibios/drivers/serial.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/platforms/chibios/drivers/serial.c b/platforms/chibios/drivers/serial.c new file mode 100644 index 0000000000..f54fbcee4e --- /dev/null +++ b/platforms/chibios/drivers/serial.c @@ -0,0 +1,278 @@ +/* + * 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(STM32_SYSCLK, 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; +} |