Added the repeated-start feature in I2C driver (#590)

Author: jmchiappa

Diff for: cores/arduino/stm32/twi.c

@@ -740,8 +740,16 @@ i2c_status_e i2c_master_write(i2c_t *obj, uint8_t dev_address,
     return i2c_IsDeviceReady(obj, dev_address, 1);
   }
 
+#if defined(I2C_OTHER_FRAME)
+  uint32_t XferOptions = obj->handle.XferOptions; // save XferOptions value, because handle can be modified by HAL, which cause issue in case of NACK from slave
+#endif
+
   do {
+#if defined(I2C_OTHER_FRAME)
+    if (HAL_I2C_Master_Seq_Transmit_IT(&(obj->handle), dev_address, data, size, XferOptions) == HAL_OK) {
+#else
     if (HAL_I2C_Master_Transmit_IT(&(obj->handle), dev_address, data, size) == HAL_OK) {
+#endif
       ret = I2C_OK;
       // wait for transfer completion
       while ((HAL_I2C_GetState(&(obj->handle)) != HAL_I2C_STATE_READY)
@@ -803,8 +811,16 @@ i2c_status_e i2c_master_read(i2c_t *obj, uint8_t dev_address, uint8_t *data, uin
   uint32_t tickstart = HAL_GetTick();
   uint32_t delta = 0;
 
+#if defined(I2C_OTHER_FRAME)
+  uint32_t XferOptions = obj->handle.XferOptions; // save XferOptions value, because handle can be modified by HAL, which cause issue in case of NACK from slave
+#endif
+
   do {
+#if defined(I2C_OTHER_FRAME)
+    if (HAL_I2C_Master_Seq_Receive_IT(&(obj->handle), dev_address, data, size, XferOptions) == HAL_OK) {
+#else
     if (HAL_I2C_Master_Receive_IT(&(obj->handle), dev_address, data, size) == HAL_OK) {
+#endif
       ret = I2C_OK;
       // wait for transfer completion
       while ((HAL_I2C_GetState(&(obj->handle)) != HAL_I2C_STATE_READY)

Diff for: libraries/Wire/src/Wire.cpp

@@ -116,7 +116,10 @@ void TwoWire::setClock(uint32_t frequency)
 
 uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity, uint32_t iaddress, uint8_t isize, uint8_t sendStop)
 {
+#if !defined(I2C_OTHER_FRAME)
   UNUSED(sendStop);
+#endif
+
   if (_i2c.isMaster == 1) {
     allocateRxBuffer(quantity);
     // error if no memory block available to allocate the buffer
@@ -146,6 +149,15 @@ uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity, uint32_t iaddres
 
     // perform blocking read into buffer
     uint8_t read = 0;
+
+#if defined(I2C_OTHER_FRAME)
+    if (sendStop == 0) {
+      _i2c.handle.XferOptions = I2C_OTHER_FRAME ;
+    } else {
+      _i2c.handle.XferOptions = I2C_OTHER_AND_LAST_FRAME;
+    }
+#endif
+
     if (I2C_OK == i2c_master_read(&_i2c, address << 1, rxBuffer, quantity)) {
       read = quantity;
     }
@@ -211,8 +223,18 @@ void TwoWire::beginTransmission(int address)
 //
 uint8_t TwoWire::endTransmission(uint8_t sendStop)
 {
+#if !defined(I2C_OTHER_FRAME)
   UNUSED(sendStop);
+#endif
   int8_t ret = 4;
+  // check transfer options and store it in the I2C handle
+#if defined(I2C_OTHER_FRAME)
+  if (sendStop == 0) {
+    _i2c.handle.XferOptions = I2C_OTHER_FRAME ;
+  } else {
+    _i2c.handle.XferOptions = I2C_OTHER_AND_LAST_FRAME;
+  }
+#endif
 
   if (_i2c.isMaster == 1) {
     // transmit buffer (blocking)