Steve Martin / libdrv_SoftI2C

Fork of SoftI2C. Added clock stretching support.

Fork of SoftI2C by Erik -

Files at this revision

API Documentation at this revision

Revision 2:b174177b2bf2, committed 2017-09-13

Comitter:
ninensei
Date:
Wed Sep 13 22:36:30 2017 +0000
Parent:
1:05473196d133
Commit message:
Added clocks stretching support

Changed in this revision

SoftI2C.cpp Show annotated file Show diff for this revision Revisions of this file 
diff -r 05473196d133 -r b174177b2bf2 SoftI2C.cpp
--- a/SoftI2C.cpp	Mon Nov 28 19:55:30 2016 +0000
+++ b/SoftI2C.cpp	Wed Sep 13 22:36:30 2017 +0000
@@ -59,11 +59,11 @@
 
 int SoftI2C::read(int ack) {
     int retval = 0;
-    _scl.output();
     
     // Shift the bits out, msb first
     for (int i = 7; i>=0; i--) {
         //SCL low
+        _scl.output();
         _scl.write(0);
         _sda.input();
         wait_us(delay_us);
@@ -73,11 +73,13 @@
         wait_us(delay_us);
         
         //SCL high again
-        _scl.write(1);
+        _scl.input();
+        while (!_scl.read());
         wait_us(delay_us << 1); //wait two delays
     }
     
     // Last cycle to set the ACK
+    _scl.output();
     _scl.write(0);
     if ( ack ) {
         _sda.output();
@@ -87,19 +89,18 @@
     }
     wait_us(delay_us << 1);
     
-    _scl.write(1);
+    _scl.input();
+    while (!_scl.read());
     wait_us(delay_us << 1);
-
     
     return retval;
 }
 
 int SoftI2C::write(int data) {
-     _scl.output();
-     
     // Shift the bits out, msb first
     for (int i = 7; i>=0; i--) {
         //SCL low
+        _scl.output();
         _scl.write(0);
         wait_us(delay_us);
         
@@ -113,18 +114,21 @@
         wait_us(delay_us);
         
         //SCL high again
-        _scl.write(1);
+        _scl.input();
+        while (!_scl.read());
         wait_us(delay_us << 1); //wait two delays
     }
     
     // Last cycle to get the ACK
+    _scl.output();
     _scl.write(0);
     wait_us(delay_us);
     
     _sda.input();
     wait_us(delay_us);
     
-    _scl.write(1);
+    _scl.input();
+    while (!_scl.read());
     wait_us(delay_us);
     int retval = ~_sda.read(); //Read the ack
     wait_us(delay_us);
@@ -139,7 +143,8 @@
         _scl.output();
         _scl.write(0);
         wait_us(delay_us << 1);
-        _scl.write(1);
+        _scl.input();
+        while (!_scl.read());
         wait_us(delay_us << 1);
     }
     // Pull SDA low
@@ -157,6 +162,7 @@
     _sda.write(0);
     wait_us(delay_us);
     _scl.input();
+    while (!_scl.read());
     wait_us(delay_us);
     _sda.input();
     wait_us(delay_us);