watch library: implement SPI

watch-library/shared/watch/watch.h

@@ -60,6 +60,7 @@
 #include "watch_adc.h"
 #include "watch_gpio.h"
 #include "watch_i2c.h"
+#include "watch_spi.h"
 #include "watch_uart.h"
 #include "watch_deepsleep.h"
 

watch-library/shared/watch/watch_spi.h

@@ -0,0 +1,59 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022 Joey Castillo
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _WATCH_SPI_H_INCLUDED
+#define _WATCH_SPI_H_INCLUDED
+////< @file watch_spi.h
+
+#include "watch.h"
+
+/** @addtogroup spi SPI Controller Driver
+  * @brief This section covers functions related to the SAM L22's built-in SPI driver, including
+  *        configuring the SPI bus and writing to / reading from devices.
+  */
+/// @{
+/** @brief Enables the SPI peripheral. Call this before attempting to interface with SPI devices.
+  */
+void watch_enable_spi(void);
+
+/** @brief Disables the SPI peripheral.
+  */
+void watch_disable_spi(void);
+
+/** @brief Sends a series of values to a device on the SPI bus.
+  * @param buf A series of unsigned bytes; the data you wish to transmit.
+  * @param length The number of bytes in buf that you wish to send.
+  * @note This function does not manage the chip select pin (usually A3).
+  */
+void watch_spi_send(uint8_t *buf, uint16_t length);
+
+/** @brief Receives a series of values from a device on the SPI bus.
+  * @param buf Storage for the incoming bytes; on return, it will contain the received data.
+  * @param length The number of bytes that you wish to receive.
+  * @note This function does not manage the chip select pin (usually A3).
+  */
+void watch_spi_receive(uint8_t *buf, uint16_t length);
+
+/// @}
+#endif