diff options
author | Nick Brassel <nick@tzarc.org> | 2021-08-29 08:20:25 +1000 |
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committer | Nick Brassel <nick@tzarc.org> | 2021-08-29 08:20:25 +1000 |
commit | f061ca497464fe85284906fb163a33eaee7a91ef (patch) | |
tree | 33ef1bfb529aed382e8526c607c4e18717f92571 /platforms/avr/drivers/spi_master.c | |
parent | ff65185dec6f97be1eb49f17cea526a0d0bbf3d6 (diff) | |
parent | 4bad375d7c09d949a9dcdd4feba147c9c7a67ec6 (diff) |
Breaking changes develop merge to master, 2021Q3 edition. (#14196)
Diffstat (limited to 'platforms/avr/drivers/spi_master.c')
-rw-r--r-- | platforms/avr/drivers/spi_master.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/platforms/avr/drivers/spi_master.c b/platforms/avr/drivers/spi_master.c new file mode 100644 index 0000000000..4e8fd3bcdf --- /dev/null +++ b/platforms/avr/drivers/spi_master.c @@ -0,0 +1,180 @@ +/* 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 "spi_master.h" + +#include "timer.h" + +#if defined(__AVR_AT90USB162__) || 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__) || defined(__AVR_ATmega328__) +# define SPI_SCK_PIN B5 +# define SPI_MOSI_PIN B3 +# define SPI_MISO_PIN B4 +#endif + +#ifndef SPI_TIMEOUT +# define SPI_TIMEOUT 100 +#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)); +} + +bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) { + if (currentSlavePin != NO_PIN || slavePin == NO_PIN) { + return false; + } + + currentSlaveConfig = 0; + + 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; + } + + uint16_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; + } + + SPCR |= currentSlaveConfig; + if (currentSlave2X) { + SPSR |= _BV(SPI2X); + } + currentSlavePin = slavePin; + setPinOutput(currentSlavePin); + writePinLow(currentSlavePin); + + return true; +} + +spi_status_t spi_write(uint8_t data) { + SPDR = data; + + uint16_t timeout_timer = timer_read(); + while (!(SPSR & _BV(SPIF))) { + if ((timer_read() - timeout_timer) >= SPI_TIMEOUT) { + return SPI_STATUS_TIMEOUT; + } + } + + return SPDR; +} + +spi_status_t spi_read() { + SPDR = 0x00; // Dummy + + uint16_t timeout_timer = timer_read(); + while (!(SPSR & _BV(SPIF))) { + if ((timer_read() - timeout_timer) >= SPI_TIMEOUT) { + return SPI_STATUS_TIMEOUT; + } + } + + return SPDR; +} + +spi_status_t spi_transmit(const uint8_t *data, uint16_t length) { + spi_status_t status; + + for (uint16_t i = 0; i < length; i++) { + status = spi_write(data[i]); + + if (status < 0) { + return status; + } + } + + return SPI_STATUS_SUCCESS; +} + +spi_status_t spi_receive(uint8_t *data, uint16_t length) { + spi_status_t status; + + for (uint16_t i = 0; i < length; i++) { + status = spi_read(); + + if (status >= 0) { + data[i] = status; + } else { + return status; + } + } + + return SPI_STATUS_SUCCESS; +} + +void spi_stop(void) { + if (currentSlavePin != NO_PIN) { + setPinOutput(currentSlavePin); + writePinHigh(currentSlavePin); + currentSlavePin = NO_PIN; + SPSR &= ~(_BV(SPI2X)); + SPCR &= ~(currentSlaveConfig); + currentSlaveConfig = 0; + currentSlave2X = false; + } +} |