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Correct Wire master repeated start behaviour #66

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Merged
merged 3 commits into from
Jan 13, 2016
Merged

Correct Wire master repeated start behaviour #66

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b993249
Add I2C Repeated Start Capability
legomanww Nov 10, 2015
9977fa3
Make white space consistent
sandeepmistry Nov 17, 2015
a2949d5
Wait for idle or bus owner state in startTransmissionWIRE instead of …
sandeepmistry Nov 18, 2015
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9 changes: 7 additions & 2 deletions cores/arduino/SERCOM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -480,8 +480,8 @@ bool SERCOM::startTransmissionWIRE(uint8_t address, SercomWireReadWriteFlag flag
// 7-bits address + 1-bits R/W
address = (address << 0x1ul) | flag;

// Wait idle bus mode
while ( !isBusIdleWIRE() );
// Wait idle or owner bus mode
while ( !isBusIdleWIRE() && !isBusOwnerWIRE() );

// Send start and address
sercom->I2CM.ADDR.bit.ADDR = address;
Expand Down Expand Up @@ -575,6 +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;
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1 change: 1 addition & 0 deletions cores/arduino/SERCOM.h
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Expand Up @@ -199,6 +199,7 @@ class SERCOM
bool isMasterWIRE( void ) ;
bool isSlaveWIRE( void ) ;
bool isBusIdleWIRE( void ) ;
bool isBusOwnerWIRE( void ) ;
bool isDataReadyWIRE( void ) ;
bool isStopDetectedWIRE( void ) ;
bool isRestartDetectedWIRE( void ) ;
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12 changes: 10 additions & 2 deletions libraries/Wire/Wire.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,11 @@ 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
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP); // Send Stop

if (stopBit)
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP); // Send Stop
}
}

return byteRead;
Expand Down Expand Up @@ -128,7 +132,11 @@ uint8_t TwoWire::endTransmission(bool stopBit)
return 3 ; // Nack or error
}
}
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);

if (stopBit)
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
}

return 0;
}
Expand Down