Diff: SoftwareI2C.h

Revision:

0:6f6cfcdfe3d8

Child:

2:8670e78c4b63

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SoftwareI2C.h	Sun Apr 01 19:21:03 2012 +0000
@@ -0,0 +1,139 @@
+/* 
+ * 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
+ */
+
+#ifndef _SOFTWARE_I2C_H_
+#define _SOFTWARE_I2C_H_
+
+#include "mbed.h"
+
+/**
+  * @brief SoftwareI2C class
+  */
+
+class SoftwareI2C {
+public:
+    SoftwareI2C(PinName sda, PinName scl);
+    ~SoftwareI2C();
+
+    void read(uint8_t device_address, uint8_t* data, uint8_t data_bytes);
+    void write(uint8_t device_address, uint8_t* data,  uint8_t data_bytes);
+    void write(uint8_t device_address, uint8_t byte);
+    void randomRead(uint8_t device_address, uint8_t start_address, uint8_t* data, uint8_t data_bytes);
+    void randomWrite(uint8_t device_address, uint8_t start_address, uint8_t* data, uint8_t data_bytes);
+    void randomWrite(uint8_t device_address, uint8_t start_address, uint8_t byte);
+    
+    uint8_t read8(uint8_t device_address, uint8_t start_address);
+    uint16_t read16(uint8_t device_address, uint8_t start_address);
+    uint32_t read24(uint8_t device_address, uint8_t start_address);
+    uint32_t read32(uint8_t device_address, uint8_t start_address);
+    
+    void setDeviceAddress(uint8_t address){
+        _device_address = address;
+    }
+
+    inline void initialise() {
+        _scl.output();
+        _sda.output();
+        
+        _sda = 1;
+        _scl = 0;
+        wait_us(10);
+
+        for ( int n = 0; n <= 3; ++n ) {
+            stop();
+        }
+    }
+
+private:
+    inline void start() {
+        _sda.output();
+        wait_us(1);
+        _scl = 1;
+        _sda = 1;
+        wait_us(1);
+        _sda = 0;
+        wait_us(1);
+        _scl = 0;
+        wait_us(1);
+    }
+
+    inline void stop() {
+        _sda.output();
+        wait_us(1);
+        _sda = 0;
+        wait_us(1);
+        _scl = 1;
+        wait_us(1);
+        _sda = 1;
+    }
+
+    inline void putByte(uint8_t byte) {
+        _sda.output();
+        for ( int n = 8; n > 0; --n) {
+            wait_us(1);
+            _sda = byte & (1 << (n-1));
+            _scl = 1;
+            wait_us(1);
+            _scl = 0;
+        }
+        _sda = 1;
+    }
+
+    inline uint8_t getByte() {
+        uint8_t byte = 0;
+
+        _sda.input();          //release the data line
+        _sda.mode(OpenDrain);
+        
+        wait_us(1);
+
+        for ( int n = 8; n > 0; --n ) {
+            _scl=1;            //set clock high
+            wait_us(1);
+            byte |= _sda << (n-1); //read the bit
+            wait_us(1);
+            _scl=0;            //set clock low
+            wait_us(1);
+        }
+
+        _sda.output();         //take data line back
+
+        return byte;
+    }
+
+    inline void giveAck() {
+        _sda.output();
+        wait_us(1);
+        _sda = 0;
+        _scl = 1;
+        wait_us(1);
+        _scl = 0;
+        _sda = 1;
+
+    }
+
+    inline bool getAck() {
+        _sda.output();
+        _sda = 1;
+        _scl = 1;
+        _sda.input();
+        _sda.mode(OpenDrain);
+        wait_us(1);
+        _scl = 0;
+
+        if(_sda != 0){return false;}
+
+        wait_us(1);
+        return true;
+    }
+
+    DigitalInOut _sda;
+    DigitalInOut _scl;
+    
+    uint8_t _device_address;
+};
+
+#endif
\ No newline at end of file