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-rw-r--r--drivers/avr/spi_master.c163
-rw-r--r--drivers/avr/spi_master.h57
2 files changed, 220 insertions, 0 deletions
diff --git a/drivers/avr/spi_master.c b/drivers/avr/spi_master.c
new file mode 100644
index 0000000000..497d50536a
--- /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;
+ }
+}
diff --git a/drivers/avr/spi_master.h b/drivers/avr/spi_master.h
new file mode 100644
index 0000000000..0bab2dc24e
--- /dev/null
+++ b/drivers/avr/spi_master.h
@@ -0,0 +1,57 @@
+/* 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/>.
+ */
+
+#pragma once
+
+#include "quantum.h"
+
+typedef int16_t spi_status_t;
+
+// Hardware SS pin is defined in the header so that user code can refer to it
+#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_SS_PIN B0
+#elif defined(__AVR_ATmega32A__)
+# define SPI_SS_PIN B4
+#elif defined(__AVR_ATmega328P__)
+# define SPI_SS_PIN B2
+#endif
+
+#define SPI_STATUS_SUCCESS (0)
+#define SPI_STATUS_ERROR (-1)
+#define SPI_STATUS_TIMEOUT (-2)
+
+#define SPI_TIMEOUT_IMMEDIATE (0)
+#define SPI_TIMEOUT_INFINITE (0xFFFF)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+void spi_init(void);
+
+void spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint8_t divisor);
+
+spi_status_t spi_write(uint8_t data, uint16_t timeout);
+
+spi_status_t spi_read(uint16_t timeout);
+
+spi_status_t spi_transmit(const uint8_t *data, uint16_t length, uint16_t timeout);
+
+spi_status_t spi_receive(uint8_t *data, uint16_t length, uint16_t timeout);
+
+void spi_stop(void);
+#ifdef __cplusplus
+}
+#endif