X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=firmware%2Fapps%2Fi2c%2Fi2c.c;h=6e1dfdea058437b79d83b98749146d0f2bde1a17;hb=96ebf28fac2e03cfee954db85282eac7b8ec8015;hp=1018c5fba8d7e28723c3105425b95bcdd5d24a73;hpb=f78ae2192de82239171b62eab19fa69c571ebd92;p=goodfet

diff --git a/firmware/apps/i2c/i2c.c b/firmware/apps/i2c/i2c.c
index 1018c5f..6e1dfde 100644
--- a/firmware/apps/i2c/i2c.c
+++ b/firmware/apps/i2c/i2c.c
@@ -73,28 +73,33 @@ app_t const i2c_app = {
 
 //#warning "Using internal resistors.  Won't work on 161x devices."
 
-//! Inits bitbanging port, must be called before using the functions below
-void I2C_Init()
+// Take control of the bus
+void I2C_Take()
 {
-  
-  //Clear SDA and SCL.
-  //Direction, not value, is used to set the value.
-  
-  SCLOUTPUT;
-  SDAOUTPUT;
-  
   I2C_CLOCK_HI();
   I2C_DATA_HI();
-  //PULLON;
+  SCLOUTPUT;
+  SDAOUTPUT;
+}
 
+void I2C_Release()
+{
+  SDAINPUT;
+  SCLINPUT;
+}
+
+//! Inits bitbanging port, must be called before using the functions below
+void I2C_Init()
+{
+  I2C_Take();
+  //PULLON;
   I2CDELAY(1);
 }
 
-// This is never called...
+// XXX This is never called...
 void I2C_Exit()
 {
-  SDAINPUT;
-  SCLINPUT;
+  I2C_Release();
   PULLOFF;
 }
 
@@ -111,12 +116,6 @@ void I2C_WriteBit( unsigned char c )
 
   I2C_CLOCK_LO();
   I2CDELAY(1);
-
-  /*if(c>0)
-   *I2C_DATA_LO();
-   *
-   *I2CDELAY(1);
-   */
 }
 
 //! Read an I2C bit.
@@ -134,6 +133,7 @@ unsigned char I2C_ReadBit()
   SDAOUTPUT;
   I2CDELAY(1);
   I2C_CLOCK_LO();
+  I2CDELAY(1);
 
   return c;
 }
@@ -161,15 +161,15 @@ unsigned char I2C_ReadBit_Wait()
   SDAOUTPUT;
   I2CDELAY(1);
   I2C_CLOCK_LO();
+  I2CDELAY(1);
 
-  return c;
+  return c?0:1;	// return true on ACK (0)
 }
 
 //! Send a START Condition
 void I2C_Start()
 {
-  // set both to high at the same time
-  SETBOTH;
+  I2C_Take();	// XXX Should probably check to see if someone else is using the bus before we do this
   I2CDELAY(3);
   
   I2C_DATA_LO();
@@ -190,6 +190,7 @@ void I2C_Stop()
 
   I2C_DATA_HI();
   I2CDELAY(1);
+  I2C_Release();
 }
 
 //! write a byte to the I2C slave device
@@ -249,15 +250,19 @@ void i2c_handle_fn( uint8_t const app,
 		break;
 	case WRITE:
 		I2C_Start();
-		for(i=0; i<len; i++)
-			cmddata[0]+=I2C_Write(cmddata[i]);
+		cmddata[0] = cmddata[0] << 1;
+		for(i=0; i<len; i++) {
+			if (!I2C_Write(cmddata[i]))		//if NACK
+				break;
+		}
 		I2C_Stop();
+		cmddata[0] = i;
 		txdata(app,verb,1);
 		break;
 	case PEEK:
 		l = cmddata[0];
 		I2C_Start();
-		unsigned char address = cmddata[1]<<1;
+		unsigned char address = cmddata[1] << 1;
 		I2C_Write(address);
 		for(i=2; i < len; i++){
 			I2C_Write(cmddata[i]);