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Make TWI_ReadPacket() use a repeated start condition rather than a full bus release/recapture after the read address has been sent.

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Fix TWI_ReadPacket() not releasing the bus correctly after all data transferred.

Make TWI_SendByte() and TWI_ReceiveByte() non-inline to reduce compiled binary size.
This commit is contained in:
Dean Camera 2011-08-31 07:17:33 +00:00
parent dc9133ad21
commit 88d022a752
2 changed files with 72 additions and 54 deletions
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63
LUFA/Drivers/Peripheral/AVR8/TWI_AVR8.c
View file

@ -97,34 +97,69 @@ uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
}
}
bool TWI_SendByte(const uint8_t Byte)
{
TWDR = Byte;
TWCR = ((1 << TWINT) | (1 << TWEN));
while (!(TWCR & (1 << TWINT)));
return ((TWSR & TW_STATUS_MASK) == TW_MT_DATA_ACK);
}
bool TWI_ReceiveByte(uint8_t* const Byte,
const bool LastByte)
{
uint8_t TWCRMask;
if (LastByte)
TWCRMask = ((1 << TWINT) | (1 << TWEN));
else
TWCRMask = ((1 << TWINT) | (1 << TWEN) | (1 << TWEA));
TWCR = TWCRMask;
while (!(TWCR & (1 << TWINT)));
*Byte = TWDR;
uint8_t Status = (TWSR & TW_STATUS_MASK);
return ((LastByte) ? (Status == TW_MR_DATA_NACK) : (Status == TW_MR_DATA_ACK));
}
uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
const uint8_t TimeoutMS,
const uint8_t* InternalAddress,
const uint8_t InternalAddressLen,
uint8_t InternalAddressLen,
uint8_t* Buffer,
uint8_t Length)
{
uint8_t ErrorCode;
if ((ErrorCode = TWI_WritePacket(SlaveAddress, TimeoutMS, InternalAddress, InternalAddressLen,
NULL, 0)) != TWI_ERROR_NoError)
if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
TimeoutMS)) == TWI_ERROR_NoError)
{
return ErrorCode;
}
if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ,
TimeoutMS)) == TWI_ERROR_NoError)
{
while (Length--)
while (InternalAddressLen--)
{
if (!(TWI_ReceiveByte(Buffer++, (Length == 1))))
{
if (!(TWI_SendByte(*(InternalAddress++))))
{
ErrorCode = TWI_ERROR_SlaveNAK;
break;
}
}
TWI_StopTransmission();
if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_READ,
TimeoutMS)) == TWI_ERROR_NoError)
{
while (Length--)
{
if (!(TWI_ReceiveByte(Buffer++, (Length == 0))))
{
ErrorCode = TWI_ERROR_SlaveNAK;
break;
}
}
TWI_StopTransmission();
}
}
return ErrorCode;
@ -145,7 +180,7 @@ uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
while (InternalAddressLen--)
{
if (!(TWI_SendByte(*(InternalAddress++))))
{
{
ErrorCode = TWI_ERROR_SlaveNAK;
break;
}