Diff: GroveColourSensor.cpp

Revision:

2:50cb56828ab9

Child:

3:a401a082d57e

diff -r 07e88c9dbbe7 -r 50cb56828ab9 GroveColourSensor.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/GroveColourSensor.cpp	Wed Apr 15 19:13:11 2015 +0000
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include "GroveColourSensor.h"
+
+/**
+*   Constructor, doesn't affect the device at all.
+*
+* @param i2c A pointer to the initialized I2C instance.
+*
+*/
+GroveColourSensor::GroveColourSensor(I2C *i2c) : i2c(i2c) {
+    /* empty*/
+}
+
+/**
+*   Powers up the color sensor.
+*
+*/
+bool GroveColourSensor::powerUp(void) {
+    static const char powerUpCommand[] = {0x80, 0x03};
+    /* turn on the color sensor */
+    return i2c->write((SEVEN_BIT_ADDRESS << 1), powerUpCommand, sizeof(powerUpCommand)) == 0;
+}
+
+/**
+*   Powers down the color sensor.
+*
+*/
+void GroveColourSensor::powerDown(void) {
+    static const char powerDownCommand[] = {0x80, 0x00};
+    /* turn on the color sensor */
+    if (i2c->write((SEVEN_BIT_ADDRESS << 1), powerDownCommand, sizeof(powerDownCommand)) != 0) {
+        error("failed to power down the sensor");
+    }
+}
+
+/**
+*   Set the gain of the color sensor.
+*
+*   The following are valid gain values:
+*   
+*   0 - 1X gain
+*   1 - 4X gain
+*   2 - 16X gain
+*   3 - 64X gain
+*   
+* @param gain The gain value specified above.
+*/
+void GroveColourSensor::setGain(uint8_t gain) {
+    // Set gain (0 Prescale)
+    char gainRegValue = 0x00 | (gain << 4);
+    
+    char gainCommand[] = {0x87, gainRegValue};
+    i2c->write((SEVEN_BIT_ADDRESS << 1), gainCommand, sizeof(gainCommand));
+}
+
+/**
+*   Read a specific color.
+*   
+* @param colour The color to red (RED, GREEN, BLUE, or CLEAR).
+*/
+uint16_t GroveColourSensor::readColour(Colour_t colour) {
+    char readColorRegistersCommand = 0xb0 + (2 * static_cast<unsigned>(colour));
+    i2c->write((SEVEN_BIT_ADDRESS << 1), &readColorRegistersCommand, 1 /* size */);
+
+    uint16_t colourValue;
+    i2c->read((SEVEN_BIT_ADDRESS << 1), reinterpret_cast<char *>(&colourValue), sizeof(uint16_t));
+    return colourValue;
+}
+
+/**
+*   Configures the color sensor to expect block reads.
+*
+*/
+void GroveColourSensor::setBlockRead() {
+    char blockReadCommand = 0xD0;
+    i2c->write((SEVEN_BIT_ADDRESS << 1), &blockReadCommand, 1);
+}
+
+/**
+*   Read the red, green, blue, and clear channels in one transaction. You must call setBlockRead() before calling this function.
+*   
+* @param sample A pointer to the RGBC instance you wish to populate.
+*/
+void GroveColourSensor::readBlock(RGBC *sample) {
+    char tmpColours[8] = {0};
+    
+    if (!i2c->read((SEVEN_BIT_ADDRESS << 1), tmpColours, sizeof(tmpColours))) {        
+        sample->ch.green = bytesTo16bit(tmpColours[0], tmpColours[1] << 8);
+        sample->ch.red = bytesTo16bit(tmpColours[2], tmpColours[3] << 8);
+        sample->ch.blue = bytesTo16bit(tmpColours[4], tmpColours[5] << 8);
+        sample->ch.clear = bytesTo16bit(tmpColours[6], tmpColours[7] << 8);
+    } else {
+        printf("I2C Read error\r\n");
+    }
+}
+
+/**
+*   Non enum version of readColour()
+*   
+* @param colour The integer corresponding to the color you wish to read.
+*/
+uint16_t GroveColourSensor::readColour(unsigned colour) {
+    if (colour >= NUM_COLORS) {
+        return 0;
+    }
+
+    return readColour(static_cast<Colour_t>(colour));
+}
+
+/**
+*   Helper function to convert two bytes into a uint16_t.
+*   
+* @param lowByte Least signficant byte.
+* @param highByte Most signficant byte.
+*/
+uint16_t GroveColourSensor::bytesTo16bit(char lowByte, char highByte) {
+    uint16_t res = 0;
+    res |= lowByte;
+    res |= highByte << 8;
+    return res;
+}