diff options
Diffstat (limited to 'drivers/avr/spi_master.c')
-rw-r--r-- | drivers/avr/spi_master.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/avr/spi_master.c b/drivers/avr/spi_master.c new file mode 100644 index 000000000..497d50536 --- /dev/null +++ b/drivers/avr/spi_master.c @@ -0,0 +1,163 @@ +/* Copyright 2020 + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#include <avr/io.h> + +#include "spi_master.h" +#include "quantum.h" +#include "timer.h" + +#if defined(__AVR_ATmega16U2__) || defined(__AVR_ATmega32U2__) || defined(__AVR_ATmega16U4__) || defined(__AVR_ATmega32U4__) || defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB647__) || defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) +# define SPI_SCK_PIN B1 +# define SPI_MOSI_PIN B2 +# define SPI_MISO_PIN B3 +#elif defined(__AVR_ATmega32A__) +# define SPI_SCK_PIN B7 +# define SPI_MOSI_PIN B5 +# define SPI_MISO_PIN B6 +#elif defined(__AVR_ATmega328P__) +# define SPI_SCK_PIN B5 +# define SPI_MOSI_PIN B3 +# define SPI_MISO_PIN B4 +#endif + +static pin_t currentSlavePin = NO_PIN; +static uint8_t currentSlaveConfig = 0; +static bool currentSlave2X = false; + +void spi_init(void) { + writePinHigh(SPI_SS_PIN); + setPinOutput(SPI_SCK_PIN); + setPinOutput(SPI_MOSI_PIN); + setPinInput(SPI_MISO_PIN); + + SPCR = (_BV(SPE) | _BV(MSTR)); +} + +void spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint8_t divisor) { + if (currentSlavePin == NO_PIN && slavePin != NO_PIN) { + if (lsbFirst) { + currentSlaveConfig |= _BV(DORD); + } + + switch (mode) { + case 1: + currentSlaveConfig |= _BV(CPHA); + break; + case 2: + currentSlaveConfig |= _BV(CPOL); + break; + case 3: + currentSlaveConfig |= (_BV(CPOL) | _BV(CPHA)); + break; + } + + uint8_t roundedDivisor = 1; + while (roundedDivisor < divisor) { + roundedDivisor <<= 1; + } + + switch (roundedDivisor) { + case 16: + currentSlaveConfig |= _BV(SPR0); + break; + case 64: + currentSlaveConfig |= _BV(SPR1); + break; + case 128: + currentSlaveConfig |= (_BV(SPR1) | _BV(SPR0)); + break; + case 2: + currentSlave2X = true; + break; + case 8: + currentSlave2X = true; + currentSlaveConfig |= _BV(SPR0); + break; + case 32: + currentSlave2X = true; + currentSlaveConfig |= _BV(SPR1); + break; + } + + SPSR |= currentSlaveConfig; + currentSlavePin = slavePin; + setPinOutput(currentSlavePin); + writePinLow(currentSlavePin); + } +} + +spi_status_t spi_write(uint8_t data, uint16_t timeout) { + SPDR = data; + + uint16_t timeout_timer = timer_read(); + while (!(SPSR & _BV(SPIF))) { + if ((timeout != SPI_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) { + return SPI_STATUS_TIMEOUT; + } + } + + return SPDR; +} + +spi_status_t spi_read(uint16_t timeout) { + SPDR = 0x00; // Dummy + + uint16_t timeout_timer = timer_read(); + while (!(SPSR & _BV(SPIF))) { + if ((timeout != SPI_TIMEOUT_INFINITE) && ((timer_read() - timeout_timer) >= timeout)) { + return SPI_STATUS_TIMEOUT; + } + } + + return SPDR; +} + +spi_status_t spi_transmit(const uint8_t *data, uint16_t length, uint16_t timeout) { + spi_status_t status = SPI_STATUS_ERROR; + + for (uint16_t i = 0; i < length; i++) { + status = spi_write(data[i], timeout); + } + + return status; +} + +spi_status_t spi_receive(uint8_t *data, uint16_t length, uint16_t timeout) { + spi_status_t status = SPI_STATUS_ERROR; + + for (uint16_t i = 0; i < length; i++) { + status = spi_read(timeout); + + if (status > 0) { + data[i] = status; + } + } + + return (status < 0) ? status : SPI_STATUS_SUCCESS; +} + +void spi_stop(void) { + if (currentSlavePin != NO_PIN) { + setPinOutput(currentSlavePin); + writePinHigh(currentSlavePin); + currentSlavePin = NO_PIN; + SPCR &= ~(currentSlaveConfig); + currentSlaveConfig = 0; + SPSR = 0; + currentSlave2X = false; + } +} |