Diff: SoftwareI2C.cpp

Revision:

5:66ca6c9b15f2

Child:

7:c3d157395c16

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftwareI2C.cpp	Tue Apr 14 12:55:29 2020 +0000
@@ -0,0 +1,212 @@
+/* 
+ * mbed Library to use a software master i2c interface on any GPIO pins
+ * Copyright (c) 2012 Christopher Pepper
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+
+#include "SoftwareI2C.h"
+
+/**
+ * @brief Initializes interface
+ * @param sda GPIO pin to use as I2C SDA
+ * @param scl GPIO pin to use as I2C SCL
+ */
+
+SoftwareI2C::SoftwareI2C(PinName sda, PinName scl) : _sda(sda) , _scl(scl) {
+    _scl.output();
+    _scl.mode(OpenDrain);
+    _sda.output();
+    _sda.mode(OpenDrain);
+
+    _device_address = 0;
+    _frequency_delay = 3;
+
+    initialise();
+}
+
+SoftwareI2C::~SoftwareI2C() {
+
+}
+
+/**
+ * @brief Read 1 or more bytes from the I2C slave
+ * @param device_address The address of the device to read from
+ * @param data An allocated array to read the data into
+ * @param data_bytes Number of bytes to read (must be equal to or less then the allocated memory in data)
+ */
+void SoftwareI2C::read(uint8_t device_address, uint8_t* data, uint8_t data_bytes) {
+    if (data == 0 || data_bytes == 0) return;
+
+    device_address = device_address | 0x01;
+    start();
+    putByte(device_address);
+    getAck();
+    for (int x = 0; x < data_bytes; ++x) {
+        data[x] = getByte();
+        if ( x < (data_bytes -1)) { //ack all but the final byte
+            giveAck();
+        }
+    }
+    stop();
+}
+
+/**
+ * @brief Write 1 or more bytes to the I2C slave
+ * @param device_address The address of the device to write to
+ * @param data An array to write the data from
+ * @param data_bytes Number of bytes to write from array
+ */
+void SoftwareI2C::write(uint8_t device_address, uint8_t* data,  uint8_t data_bytes) {
+    if (data == 0 || data_bytes == 0) return;
+
+    device_address = device_address & 0xFE;
+    start();
+    putByte(device_address);
+    getAck();
+    for ( int x = 0; x < data_bytes; ++x ) {
+        putByte(data[x]);
+        getAck();
+    }
+    stop();
+}
+
+/**
+ * @brief Write 1 byte to the I2C slave
+ * @param device_address The address of the device to write to
+ * @param byte The data to write
+ */
+void SoftwareI2C::write(uint8_t device_address, uint8_t byte) {
+    device_address = device_address & 0xFE;
+    start();
+    putByte(device_address);
+    getAck();
+    putByte(byte);
+    getAck();
+    stop();
+}
+
+/**
+ * @brief Read 1 or more bytes from the I2C slave at the specified memory address
+ * @param device_address The address of the device to read from
+ * @param start_address The memory address to read from
+ * @param data The allocated array to read into
+ * @param data_bytes The number of bytes to read
+ */
+void SoftwareI2C::randomRead(uint8_t device_address, uint8_t start_address, uint8_t* data, uint8_t data_bytes) {
+    if (data == 0 || data_bytes == 0) return;
+
+    device_address = device_address & 0xFE;
+    start();
+    putByte(device_address);
+    if (!getAck()) {
+        return;
+    }
+    putByte(start_address);
+    if (!getAck()) {
+        return;
+    }
+
+    device_address=device_address | 0x01;
+    start();
+    putByte(device_address);
+    if (!getAck()) {
+        return;
+    }
+    for ( int x = 0; x < data_bytes; ++x) {
+        data[x] = getByte();
+        if (x != (data_bytes - 1)) giveAck();
+    }
+    stop();
+}
+
+/**
+ * @brief Write 1 byte to the I2C slave at the specified memory address
+ * @param device_address The address of the device to write to
+ * @param start_address The memory address to write to
+ * @param byte The data to write
+ */
+void SoftwareI2C::randomWrite(uint8_t device_address, uint8_t start_address, uint8_t byte) {
+    device_address = device_address & 0xFE;
+    start();
+    putByte(device_address);
+    getAck();
+    putByte(start_address);
+    getAck();
+    putByte(byte);
+    getAck();
+    stop();
+}
+
+/**
+ * @brief Write 1 or more bytes to the I2C slave at the specified memory address
+ * @param device_address The address of the device to write to
+ * @param start_address The memory address to write to
+ * @param data The data to write
+ * @param data_bytes The number of bytes to write
+ */
+void SoftwareI2C::randomWrite(uint8_t device_address, uint8_t start_address, uint8_t* data, uint8_t data_bytes) {
+    if (data == 0 || data_bytes == 0) return;
+
+    device_address = device_address & 0xFE;
+    start();
+    putByte(device_address);
+    getAck();
+    putByte(start_address);
+    getAck();
+    for ( int x = 0; x <= data_bytes; ++x ) {
+        putByte(data[x]);
+        getAck();
+    }
+    stop();
+}
+
+/**
+ * @brief Read 2 bytes from the I2C slave at the specified memory address and return them as an 16bit unsigned integer
+ * @param device_address The address of the device to read from
+ * @param start_address The memory address to read from
+ * @return MSB 16bit unsigned integer
+ */
+uint16_t SoftwareI2C::read16(uint8_t device_address, uint8_t start_address) {
+    uint8_t short_array[2] = {0, 0};
+    randomRead(device_address, start_address, short_array, 2 );
+    uint16_t value = 0;
+    value = short_array[0] << 8;
+    value |= short_array[1];
+
+    return value;
+}
+
+/**
+ * @brief Read 3 bytes from the I2C slave at the specified memory address and return them as an 32bit unsigned integer
+ * @param device_address The address of the device to read from
+ * @param start_address The memory address to read from
+ * @return MSB 32bit unsigned integer 
+ */
+uint32_t SoftwareI2C::read24(uint8_t device_address, uint8_t start_address) {
+    uint8_t value_array[4] = {0, 0, 0};
+    randomRead(device_address, start_address, value_array, 3 );
+    uint32_t value = 0;
+    value = value_array[0] << 16;
+    value |= value_array[1] << 8;
+    value |= value_array[2];
+
+    return value;
+}
+
+/**
+ * @brief Read 4 bytes from the I2C slave at the specified memory address and return them as an 32bit unsigned integer
+ * @param device_address The address of the device to read from
+ * @param start_address The memory address to read from
+ * @return MSB 32bit unsigned integer
+ */
+uint32_t SoftwareI2C::read32(uint8_t device_address, uint8_t start_address) {
+    uint8_t value_array[4] = {0, 0, 0, 0};
+    randomRead(device_address, start_address, value_array, 4 );
+    uint32_t value = 0;
+    value = value_array[0] << 24;
+    value |= value_array[1] << 16;
+    value |= value_array[2] << 8;
+    value |= value_array[3];
+
+    return value;
+}
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