Merge pull request #302 from bmarquismarkail/rcmclone

Adding i2C repeated start condition from @bmarquismarkail

Author: rogerclarkmelbourne

STM32F1/libraries/Wire/HardWire.cpp

@@ -38,7 +38,7 @@
 
 #include "HardWire.h"
 
-uint8 HardWire::process() {
+uint8 HardWire::process(uint8 stop) {
     int8 res = i2c_master_xfer(sel_hard, &itc_msg, 1, 0);
     if (res == I2C_ERROR_PROTOCOL) {
         if (sel_hard->error_flags & I2C_SR1_AF) { /* NACK */
@@ -55,6 +55,10 @@ uint8 HardWire::process() {
     return res;
 }
 
+uint8 HardWire::process(){
+	return process(true);
+}
+
 // TODO: Add in Error Handling if devsel is out of range for other Maples
 HardWire::HardWire(uint8 dev_sel, uint8 flags) {
     if (dev_sel == 1) {

STM32F1/libraries/Wire/HardWire.h

@@ -52,6 +52,7 @@ class HardWire : public WireBase {
      * Processes the incoming I2C message defined by WireBase to the
      * hardware. If an error occured, restart the I2C device.
      */
+    uint8 process(uint8);
     uint8 process();
 public:
     /*

STM32F1/libraries/Wire/Wire.cpp

@@ -40,6 +40,9 @@
   * Updated by Roger Clark. 20141111. Fixed issue when process() returned because of missing ACK (often caused by invalid device address being used), caused SCL to be left
   * LOW so that in the next call to process() , the first clock pulse was not sent, because SCL was LOW when it should have been high.
   */
+ /*
+  * Updated by Brandon Green. 20172306. Implementing the repeated start functionality.
+  */
 
 #include "Wire.h"
 
@@ -76,6 +79,12 @@ void TwoWire::i2c_stop() {
     set_sda(HIGH);
 }
 
+void TwoWire::i2c_repeated_start() {
+    set_sda(HIGH);
+    set_scl(HIGH);
+    set_sda(LOW);
+}
+
 bool TwoWire::i2c_get_ack() {
     set_scl(LOW);
     set_sda(HIGH);
@@ -121,7 +130,8 @@ void TwoWire::i2c_shift_out(uint8 val) {
     }
 }
 
-uint8 TwoWire::process() {
+//process needs to be updated for repeated start.
+uint8 TwoWire::process(uint8 stop) {
     itc_msg.xferred = 0;
 
     uint8 sla_addr = (itc_msg.addr << 1);
@@ -162,10 +172,18 @@ uint8 TwoWire::process() {
             itc_msg.xferred++;
         }
     }
-    i2c_stop();
+    if(stop == true)
+		i2c_stop();
+    else i2c_repeated_start();
+	
     return SUCCESS;
 }
 
+// For compatibility with legacy code
+uint8 TwoWire::process(){
+	return process(true);
+}
+
 // TODO: Add in Error Handling if pins is out of range for other Maples
 // TODO: Make delays more capable
 TwoWire::TwoWire(uint8 scl, uint8 sda, uint8 delay) : i2c_delay(delay) {

STM32F1/libraries/Wire/Wire.h

@@ -86,7 +86,12 @@ class TwoWire : public WireBase {
      * Creates a Stop condition on the bus
      */
     void  i2c_stop();
-
+    
+    /*
+     * Created a Repeated Start condition on the bus
+     */
+    void i2c_repeated_start();
+    
     /*
      * Gets an ACK condition from a slave device on the bus
      */
@@ -119,6 +124,7 @@ class TwoWire : public WireBase {
     /*
      * Processes the incoming I2C message defined by WireBase
      */
+    uint8 process(uint8);
     uint8 process();
  public:
     /*

STM32F1/libraries/Wire/WireBase.cpp

@@ -59,17 +59,21 @@ void WireBase::beginTransmission(int slave_address) {
     beginTransmission((uint8)slave_address);
 }
 
-uint8 WireBase::endTransmission(void) {
+uint8 WireBase::endTransmission(uint8 stop) {
     uint8 retVal;
     if (tx_buf_overflow) {
         return EDATA;
     }
-    retVal = process();// Changed so that the return value from process is returned by this function see also the return line below
+    retVal = process(stop);// Changed so that the return value from process is returned by this function see also the return line below
     tx_buf_idx = 0;
     tx_buf_overflow = false;
     return retVal;//SUCCESS;
 }
 
+uint8 WireBase::endTransmission(){
+    endTransmission(true);
+}
+
 //TODO: Add the ability to queue messages (adding a boolean to end of function
 // call, allows for the Arduino style to stay while also giving the flexibility
 // to bulk send

STM32F1/libraries/Wire/WireBase.h

@@ -65,6 +65,7 @@ class WireBase { // Abstraction is awesome!
     boolean tx_buf_overflow;
 
     // Force derived classes to define process function
+    virtual uint8 process(uint8) = 0;
     virtual uint8 process() = 0;
 public:
     WireBase() {}
@@ -90,6 +91,7 @@ class WireBase { // Abstraction is awesome!
      * Call the process function to process the message if the TX
      * buffer has not overflowed.
      */
+    uint8 endTransmission(uint8);
     uint8 endTransmission(void);
 
     /*