Chris Pepper / SoftwareI2C

First release of a Software I2C implementation, Tested and confirmed to work with the BMP085 Barometric Pressure Sensor

Dependents:   SoftwareI2C_Test

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

Diff: SoftwareI2C.h

Revision:
2:8670e78c4b63
Parent:
0:6f6cfcdfe3d8
--- a/SoftwareI2C.h	Sun Apr 01 19:27:03 2012 +0000
+++ b/SoftwareI2C.h	Sun Apr 01 22:52:47 2012 +0000
@@ -33,6 +33,10 @@
     void setDeviceAddress(uint8_t address){
         _device_address = address;
     }
+    
+    void setFrequency(uint32_t frequency){
+        _frequency_delay = 1000000 / frequency;
+    }
 
     inline void initialise() {
         _scl.output();
@@ -40,7 +44,7 @@
         
         _sda = 1;
         _scl = 0;
-        wait_us(10);
+        wait_us(_frequency_delay);
 
         for ( int n = 0; n <= 3; ++n ) {
             stop();
@@ -50,33 +54,33 @@
 private:
     inline void start() {
         _sda.output();
-        wait_us(1);
+        wait_us(_frequency_delay);
         _scl = 1;
         _sda = 1;
-        wait_us(1);
+        wait_us(_frequency_delay);
         _sda = 0;
-        wait_us(1);
+        wait_us(_frequency_delay);
         _scl = 0;
-        wait_us(1);
+        wait_us(_frequency_delay);
     }
 
     inline void stop() {
         _sda.output();
-        wait_us(1);
+        wait_us(_frequency_delay);
         _sda = 0;
-        wait_us(1);
+        wait_us(_frequency_delay);
         _scl = 1;
-        wait_us(1);
+        wait_us(_frequency_delay);
         _sda = 1;
     }
 
     inline void putByte(uint8_t byte) {
         _sda.output();
         for ( int n = 8; n > 0; --n) {
-            wait_us(1);
+            wait_us(_frequency_delay);
             _sda = byte & (1 << (n-1));
             _scl = 1;
-            wait_us(1);
+            wait_us(_frequency_delay);
             _scl = 0;
         }
         _sda = 1;
@@ -88,15 +92,15 @@
         _sda.input();          //release the data line
         _sda.mode(OpenDrain);
         
-        wait_us(1);
+        wait_us(_frequency_delay);
 
         for ( int n = 8; n > 0; --n ) {
             _scl=1;            //set clock high
-            wait_us(1);
+            wait_us(_frequency_delay);
             byte |= _sda << (n-1); //read the bit
-            wait_us(1);
+            wait_us(_frequency_delay);
             _scl=0;            //set clock low
-            wait_us(1);
+            wait_us(_frequency_delay);
         }
 
         _sda.output();         //take data line back
@@ -106,10 +110,10 @@
 
     inline void giveAck() {
         _sda.output();
-        wait_us(1);
+        wait_us(_frequency_delay);
         _sda = 0;
         _scl = 1;
-        wait_us(1);
+        wait_us(_frequency_delay);
         _scl = 0;
         _sda = 1;
 
@@ -121,12 +125,12 @@
         _scl = 1;
         _sda.input();
         _sda.mode(OpenDrain);
-        wait_us(1);
+        wait_us(_frequency_delay);
         _scl = 0;
 
         if(_sda != 0){return false;}
 
-        wait_us(1);
+        wait_us(_frequency_delay);
         return true;
     }
 
@@ -134,6 +138,7 @@
     DigitalInOut _scl;
     
     uint8_t _device_address;
+    uint32_t _frequency_delay;
 };
 
 #endif
\ No newline at end of file