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
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/*
LUFA Library
Copyright (C) Dean Camera, 2012.
dean [at] fourwalledcubicle [dot] com
www.lufa-lib.org
*/
/*
Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com)
Permission to use, copy, modify, distribute, and sell this
software and its documentation for any purpose is hereby granted
without fee, provided that the above copyright notice appear in
all copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the name of the author not be used in
advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
The author disclaim all warranties with regard to this
software, including all implied warranties of merchantability
and fitness. In no event shall the author be liable for any
special, indirect or consequential damages or any damages
whatsoever resulting from loss of use, data or profits, whether
in an action of contract, negligence or other tortious action,
arising out of or in connection with the use or performance of
this software.
*/
#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;
}
}
}
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,
uint8_t InternalAddressLen,
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;
}
}
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;
}
|
