Merge pull request #5 from Sensirion/update-raspi-pico-sample-implementation

Update Raspberry Pi Pico sample implementation

Author: psachs

sample-implementations/RaspberryPi_Pico/README.md

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+### Project Setup
+
+To program the Raspberry Pi Pico, we use the Raspberry Pi Pico VS Code extension. 
+
+Follow these instructions to flash the example:
+
+1. Open the Raspberry Pi Pico VS Code extension and create a new **C/C++ project**.
+2. Select your board type.
+3. Enable the **I2C interface** feature.
+4. Enable **Console over USB**.
+5. Click **Create**.
+6. Copy all driver .h and .c files into the new pico project.
+7. Copy the example usage into the pico project
+8. Replace the sensirion_i2c_hal.c file with the file from the Raspberry Pi Pico sample implementation
+9. In your CMakeLists.txt, replace the add_executable block with:
+    ```cmake
+    add_executable(<project_name>
+        sen5x_i2c_example_usage.c
+        sensirion_i2c.c
+        sensirion_i2c_hal.c
+        sen5x_i2c.c
+        sensirion_common.c
+    )
+    ```
+10. Replace <project_name> with your project name
+11. Connect your sensor and flash the firmware.
+
+Once flashed successfully, the Raspberry Pi Pico will print sensor readings over the USB serial console.
+
+### Connecting the Sensor
+
+- SDA: GPIO4 (Pin 6)
+- SCL: GPIO5 (Pin 7)

sample-implementations/RaspberryPi_Pico/sensirion_i2c_hal.c

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+#include "hardware/i2c.h"
+#include "pico/stdlib.h"
+/*
+ * Copyright (c) 2018, Sensirion AG
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Sensirion AG nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "sensirion_common.h"
+#include "sensirion_config.h"
+#include "sensirion_i2c_hal.h"
+
+#define I2C_PORT i2c0
+#define PIN_I2C_SDA 4
+#define PIN_I2C_SCL 5
+
+/**
+ * Select the current i2c bus by index.
+ * All following i2c operations will be directed at that bus.
+ *
+ * THE IMPLEMENTATION IS OPTIONAL ON SINGLE-BUS SETUPS (all sensors on the same
+ * bus)
+ *
+ * @param bus_idx   Bus index to select
+ * @returns         0 on success, an error code otherwise
+ */
+int16_t sensirion_i2c_hal_select_bus(uint8_t bus_idx) {
+    /* TODO:IMPLEMENT or leave empty if all sensors are located on one single
+     * bus
+     */
+    return NOT_IMPLEMENTED_ERROR;
+}
+
+/**
+ * Initialize all hard- and software components that are needed for the I2C
+ * communication.
+ */
+void sensirion_i2c_hal_init(void) {
+    stdio_init_all();
+
+    // I2C Initialisation. Using it at 400Khz.
+    i2c_init(I2C_PORT, 400 * 1000);
+
+    gpio_set_function(PIN_I2C_SDA, GPIO_FUNC_I2C);
+    gpio_set_function(PIN_I2C_SCL, GPIO_FUNC_I2C);
+    gpio_pull_up(PIN_I2C_SDA);
+    gpio_pull_up(PIN_I2C_SCL);
+}
+
+/**
+ * Release all resources initialized by sensirion_i2c_hal_init().
+ */
+void sensirion_i2c_hal_free(void) {
+    i2c_deinit(I2C_PORT);
+    gpio_set_function(PIN_I2C_SDA, GPIO_FUNC_NULL);
+    gpio_set_function(PIN_I2C_SCL, GPIO_FUNC_NULL);
+    gpio_disable_pulls(PIN_I2C_SDA);
+    gpio_disable_pulls(PIN_I2C_SCL);
+}
+
+/**
+ * Execute one read transaction on the I2C bus, reading a given number of bytes.
+ * If the device does not acknowledge the read command, an error shall be
+ * returned.
+ *
+ * @param address 7-bit I2C address to read from
+ * @param data    pointer to the buffer where the data is to be stored
+ * @param count   number of bytes to read from I2C and store in the buffer
+ * @returns 0 on success, error code otherwise
+ */
+int8_t sensirion_i2c_hal_read(uint8_t address, uint8_t* data, uint8_t count) {
+    int status = i2c_read_blocking(i2c_default, address, data, count, false);
+
+    if (status <= 0)
+        return 1;
+    else
+        return 0;
+}
+
+/**
+ * Execute one write transaction on the I2C bus, sending a given number of
+ * bytes. The bytes in the supplied buffer must be sent to the given address. If
+ * the slave device does not acknowledge any of the bytes, an error shall be
+ * returned.
+ *
+ * @param address 7-bit I2C address to write to
+ * @param data    pointer to the buffer containing the data to write
+ * @param count   number of bytes to read from the buffer and send over I2C
+ * @returns 0 on success, error code otherwise
+ */
+int8_t sensirion_i2c_hal_write(uint8_t address, const uint8_t* data,
+                               uint8_t count) {
+    // I2C Default is used (I2C0).
+    int status = i2c_write_blocking(i2c_default, address, data, count, true);
+
+    if (status <= 0)
+        return 1;
+    else
+        return 0;
+}
+
+/**
+ * Sleep for a given number of microseconds. The function should delay the
+ * execution for at least the given time, but may also sleep longer.
+ *
+ * Despite the unit, a <10 millisecond precision is sufficient.
+ *
+ * @param useconds the sleep time in microseconds
+ */
+void sensirion_i2c_hal_sleep_usec(uint32_t useconds) {
+    sleep_ms(useconds / 1000);
+}