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.
55 lines
1.0 KiB
55 lines
1.0 KiB
/*
|
|
Copyright (C) Dean Camera, 2010.
|
|
|
|
dean [at] fourwalledcubicle [dot] com
|
|
www.fourwalledcubicle.com
|
|
*/
|
|
|
|
#include "TWI.h"
|
|
|
|
bool TWI_StartTransmission(uint8_t SlaveAddress)
|
|
{
|
|
for (;;)
|
|
{
|
|
uint8_t IterationsRemaining = 50;
|
|
bool BusCaptured = false;
|
|
|
|
while (IterationsRemaining-- && !BusCaptured)
|
|
{
|
|
TWCR = ((1 << TWINT) | (1 << TWSTA) | (1 << TWEN));
|
|
while (!(TWCR & (1 << TWINT)));
|
|
|
|
switch (TWSR & TW_STATUS_MASK)
|
|
{
|
|
case TW_START:
|
|
case TW_REP_START:
|
|
BusCaptured = true;
|
|
break;
|
|
case TW_MT_ARB_LOST:
|
|
continue;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (!(BusCaptured))
|
|
return false;
|
|
|
|
TWDR = SlaveAddress;
|
|
TWCR = ((1 << TWINT) | (1 << TWEN));
|
|
while (!(TWCR & (1 << TWINT)));
|
|
|
|
GPIOR0 = (TWSR & TW_STATUS_MASK);
|
|
|
|
switch (TWSR & TW_STATUS_MASK)
|
|
{
|
|
case TW_MT_SLA_ACK:
|
|
case TW_MR_SLA_ACK:
|
|
return true;
|
|
default:
|
|
TWI_StopTransmission();
|
|
break;
|
|
}
|
|
}
|
|
}
|