You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
145 lines
3.0 KiB
145 lines
3.0 KiB
/*
|
|
Copyright (C) Dean Camera, 2011.
|
|
|
|
dean [at] fourwalledcubicle [dot] com
|
|
www.lufa-lib.org
|
|
*/
|
|
|
|
#define __INCLUDE_FROM_TWI_C
|
|
#include "TWI.h"
|
|
|
|
uint8_t TWI_StartTransmission(const uint8_t SlaveAddress,
|
|
const uint8_t TimeoutMS)
|
|
{
|
|
for (;;)
|
|
{
|
|
bool BusCaptured = false;
|
|
uint16_t TimeoutRemaining;
|
|
|
|
TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
|
|
|
|
TimeoutRemaining = (TimeoutMS * 100);
|
|
while (TimeoutRemaining-- && !(BusCaptured))
|
|
{
|
|
if (TWCR & (1 << TWINT))
|
|
{
|
|
switch (TWSR & TW_STATUS_MASK)
|
|
{
|
|
case TW_START:
|
|
case TW_REP_START:
|
|
BusCaptured = true;
|
|
break;
|
|
case TW_MT_ARB_LOST:
|
|
TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
|
|
continue;
|
|
default:
|
|
TWCR = (1 << TWEN);
|
|
return TWI_ERROR_BusFault;
|
|
}
|
|
}
|
|
|
|
_delay_us(10);
|
|
}
|
|
|
|
if (!(TimeoutRemaining))
|
|
{
|
|
TWCR = (1 << TWEN);
|
|
return TWI_ERROR_BusCaptureTimeout;
|
|
}
|
|
|
|
TWDR = SlaveAddress;
|
|
TWCR = ((1 << TWINT) | (1 << TWEN));
|
|
|
|
TimeoutRemaining = (TimeoutMS * 100);
|
|
while (TimeoutRemaining--)
|
|
{
|
|
if (TWCR & (1 << TWINT))
|
|
break;
|
|
|
|
_delay_us(10);
|
|
}
|
|
|
|
if (!(TimeoutRemaining))
|
|
return TWI_ERROR_SlaveResponseTimeout;
|
|
|
|
switch (TWSR & TW_STATUS_MASK)
|
|
{
|
|
case TW_MT_SLA_ACK:
|
|
case TW_MR_SLA_ACK:
|
|
return TWI_ERROR_NoError;
|
|
default:
|
|
TWCR = ((1 << TWINT) | (1 << TWSTO) | (1 << TWEN));
|
|
return TWI_ERROR_SlaveNotReady;
|
|
}
|
|
}
|
|
}
|
|
|
|
uint8_t TWI_ReadPacket(const uint8_t SlaveAddress,
|
|
const uint8_t TimeoutMS,
|
|
const uint8_t* InternalAddress,
|
|
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)
|
|
{
|
|
return ErrorCode;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
uint8_t TWI_WritePacket(const uint8_t SlaveAddress,
|
|
const uint8_t TimeoutMS,
|
|
const uint8_t* InternalAddress,
|
|
uint8_t InternalAddressLen,
|
|
const uint8_t* Buffer,
|
|
uint8_t Length)
|
|
{
|
|
uint8_t ErrorCode;
|
|
|
|
if ((ErrorCode = TWI_StartTransmission((SlaveAddress & TWI_DEVICE_ADDRESS_MASK) | TWI_ADDRESS_WRITE,
|
|
TimeoutMS)) == TWI_ERROR_NoError)
|
|
{
|
|
while (InternalAddressLen--)
|
|
{
|
|
if (!(TWI_SendByte(*(InternalAddress++))))
|
|
{
|
|
ErrorCode = TWI_ERROR_SlaveNAK;
|
|
break;
|
|
}
|
|
}
|
|
|
|
while (Length--)
|
|
{
|
|
if (!(TWI_SendByte(*(Buffer++))))
|
|
{
|
|
ErrorCode = TWI_ERROR_SlaveNAK;
|
|
break;
|
|
}
|
|
}
|
|
|
|
TWI_StopTransmission();
|
|
}
|
|
|
|
return ErrorCode;
|
|
}
|