blob: dda88f8babd7598e37ebc862547f4859c4cd6727 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
/*
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;
}
}
}
|
