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+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 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.
+ */
+////< @file watch_i2c.h
+
+/** @addtogroup i2c I2C Controller Driver
+  * @brief This section covers functions related to the SAM L22's built-I2C driver, including
+  *        configuring the I2C bus, putting values directly on the bus and reading data from
+  *        registers on I2C devices.
+  */
+/// @{
+/** @brief Enables the I2C peripheral. Call this before attempting to interface with I2C devices.
+  */
+void watch_enable_i2c();
+
+/** @brief Sends a series of values to a device on the I2C bus.
+  * @param addr The address of the device you wish to talk to.
+  * @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.
+  */
+void watch_i2c_send(int16_t addr, uint8_t *buf, uint16_t length);
+
+/** @brief Receives a series of values from a device on the I2C bus.
+  * @param addr The address of the device you wish to hear from.
+  * @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.
+  */
+void watch_i2c_receive(int16_t addr, uint8_t *buf, uint16_t length);
+
+/** @brief Writes a byte to a register in an I2C device.
+  * @param addr The address of the device you wish to address.
+  * @param reg The register on the device that you wish to set.
+  * @param data The value that you wish to set the register to.
+  */
+void watch_i2c_write8(int16_t addr, uint8_t reg, uint8_t data);
+
+/** @brief Reads a byte from a register in an I2C device.
+  * @param addr The address of the device you wish to address.
+  * @param reg The register on the device that you wish to read.
+  * @return An unsigned byte representing the value of the register that was read.
+  */
+uint8_t watch_i2c_read8(int16_t addr, uint8_t reg);
+
+/** @brief Reads an unsigned little-endian word from a register in an I2C device.
+  * @param addr The address of the device you wish to address.
+  * @param reg The register on the device that you wish to read.
+  * @return An unsigned word representing the value of the register that was read.
+  * @note This reads two bytes into the word in bus order. If the device returns
+          the LSB first and then the MSB, you can use this value as returned.
+          If the device returns the data in big-endian order or uses some other
+          kind of fancy bit packing, you may need to shuffle some bits around.
+  */
+uint16_t watch_i2c_read16(int16_t addr, uint8_t reg);
+
+/** @brief Reads three bytes as an unsigned little-endian int from a register in an I2C device.
+  * @param addr The address of the device you wish to address.
+  * @param reg The register on the device that you wish to read.
+  * @return An unsigned word representing the value of the register that was read.
+  * @note This reads three bytes into the word in bus order. If the device returns
+          these bytes LSB first, you can use this value as returned. If there is a
+          sign bit, the device returns the data in big-endian order, or it uses some
+          other kind of fancy bit packing, you may need to shuffle some bits around.
+  */
+uint32_t watch_i2c_read24(int16_t addr, uint8_t reg);
+
+
+/** @brief Reads an unsigned little-endian int from a register in an I2C device.
+  * @param addr The address of the device you wish to address.
+  * @param reg The register on the device that you wish to read.
+  * @return An unsigned word representing the value of the register that was read.
+  * @note This reads three bytes into the word in bus order. If the device returns
+          these bytes LSB first, you can use this value as returned. If the device
+          returns the data in big-endian order, or it uses some other kind of fancy
+          bit packing, you may need to shuffle some bits around.
+  */
+uint32_t watch_i2c_read32(int16_t addr, uint8_t reg);
+/// @}