From a2949d505f977ab267ce28c4b02ad17a4088a4e1 Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@arduino.cc>
Date: Wed, 18 Nov 2015 09:19:04 -0500
Subject: [PATCH] Wait for idle or bus owner state in startTransmissionWIRE
instead of storing repeated start state.
---
cores/arduino/SERCOM.cpp | 14 +++++++-------
cores/arduino/SERCOM.h | 2 +-
libraries/Wire/Wire.cpp | 6 ++----
libraries/Wire/Wire.h | 1 -
4 files changed, 10 insertions(+), 13 deletions(-)
diff --git a/cores/arduino/SERCOM.cpp b/cores/arduino/SERCOM.cpp
index b45ecdc4..dacae227 100644
--- a/cores/arduino/SERCOM.cpp
+++ b/cores/arduino/SERCOM.cpp
@@ -476,17 +476,12 @@ void SERCOM::prepareCommandBitsWire(SercomMasterCommandWire cmd)
}
bool SERCOM::startTransmissionWIRE(uint8_t address, SercomWireReadWriteFlag flag)
-{
- return startTransmissionWIRE(address, flag, false);
-}
-
-bool SERCOM::startTransmissionWIRE(uint8_t address, SercomWireReadWriteFlag flag, bool repeatedStart)
{
// 7-bits address + 1-bits R/W
address = (address << 0x1ul) | flag;
- // Wait idle bus mode
- while ( !repeatedStart && !isBusIdleWIRE());
+ // Wait idle or owner bus mode
+ while ( !isBusIdleWIRE() && !isBusOwnerWIRE() );
// Send start and address
sercom->I2CM.ADDR.bit.ADDR = address;
@@ -580,6 +575,11 @@ bool SERCOM::isBusIdleWIRE( void )
return sercom->I2CM.STATUS.bit.BUSSTATE == WIRE_IDLE_STATE;
}
+bool SERCOM::isBusOwnerWIRE( void )
+{
+ return sercom->I2CM.STATUS.bit.BUSSTATE == WIRE_OWNER_STATE;
+}
+
bool SERCOM::isDataReadyWIRE( void )
{
return sercom->I2CS.INTFLAG.bit.DRDY;
diff --git a/cores/arduino/SERCOM.h b/cores/arduino/SERCOM.h
index 307f5a9c..26a437e8 100644
--- a/cores/arduino/SERCOM.h
+++ b/cores/arduino/SERCOM.h
@@ -194,12 +194,12 @@ class SERCOM
void prepareAckBitWIRE( void ) ;
void prepareCommandBitsWire(SercomMasterCommandWire cmd);
bool startTransmissionWIRE(uint8_t address, SercomWireReadWriteFlag flag) ;
- bool startTransmissionWIRE(uint8_t address, SercomWireReadWriteFlag flag, bool repeatedStart) ;
bool sendDataMasterWIRE(uint8_t data) ;
bool sendDataSlaveWIRE(uint8_t data) ;
bool isMasterWIRE( void ) ;
bool isSlaveWIRE( void ) ;
bool isBusIdleWIRE( void ) ;
+ bool isBusOwnerWIRE( void ) ;
bool isDataReadyWIRE( void ) ;
bool isStopDetectedWIRE( void ) ;
bool isRestartDetectedWIRE( void ) ;
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp
index c4747947..21d39f71 100644
--- a/libraries/Wire/Wire.cpp
+++ b/libraries/Wire/Wire.cpp
@@ -68,7 +68,7 @@ uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity, bool stopBit)
size_t byteRead = 0;
- if(sercom->startTransmissionWIRE(address, WIRE_READ_FLAG, repeatedStart))
+ if(sercom->startTransmissionWIRE(address, WIRE_READ_FLAG))
{
// Read first data
rxBuffer.store_char(sercom->readDataWIRE());
@@ -83,7 +83,6 @@ uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity, bool stopBit)
sercom->prepareNackBitWIRE(); // Prepare NACK to stop slave transmission
//sercom->readDataWIRE(); // Clear data register to send NACK
- repeatedStart = !stopBit;
if (stopBit)
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP); // Send Stop
@@ -117,7 +116,7 @@ uint8_t TwoWire::endTransmission(bool stopBit)
transmissionBegun = false ;
// Start I2C transmission
- if ( !sercom->startTransmissionWIRE( txAddress, WIRE_WRITE_FLAG, repeatedStart ) )
+ if ( !sercom->startTransmissionWIRE( txAddress, WIRE_WRITE_FLAG ) )
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
return 2 ; // Address error
@@ -134,7 +133,6 @@ uint8_t TwoWire::endTransmission(bool stopBit)
}
}
- repeatedStart = !stopBit;
if (stopBit)
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
diff --git a/libraries/Wire/Wire.h b/libraries/Wire/Wire.h
index bc2968ab..ab7ccae6 100644
--- a/libraries/Wire/Wire.h
+++ b/libraries/Wire/Wire.h
@@ -67,7 +67,6 @@ class TwoWire : public Stream
uint8_t _uc_pinSCL;
bool transmissionBegun;
- bool repeatedStart;
// RX Buffer
RingBuffer rxBuffer;
--
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