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
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Linus Nielsen Feltzing
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "lcd.h"
#include "sh7034.h"
#include "kernel.h"
#include "debug.h"
#define PB13 0x2000
#define PB7 0x0080
#define PB5 0x0020
/* cute little functions */
#define SDA_LO (PBDR &= ~PB7)
#define SDA_HI (PBDR |= PB7)
#define SDA_INPUT (PBIOR &= ~PB7)
#define SDA_OUTPUT (PBIOR |= PB7)
#define SDA (PBDR & PB7)
#define SCL_INPUT (PBIOR &= ~PB13)
#define SCL_OUTPUT (PBIOR |= PB13)
#define SCL_LO (PBDR &= ~PB13)
#define SCL_HI (PBDR |= PB13)
#define SCL (PBDR & PB13)
/* arbitrary delay loop */
#define DELAY do { int _x; for(_x=0;_x<20;_x++);} while (0)
static struct mutex i2c_mtx;
void i2c_begin(void)
{
mutex_lock(&i2c_mtx);
}
void i2c_end(void)
{
mutex_unlock(&i2c_mtx);
}
void i2c_start(void)
{
SDA_OUTPUT;
SDA_HI;
SCL_HI;
SDA_LO;
DELAY;
SCL_LO;
}
void i2c_stop(void)
{
SDA_LO;
SCL_HI;
DELAY;
SDA_HI;
}
void i2c_init(void)
{
int i;
/* make PB5, PB7 & PB13 general I/O */
PBCR1 &= ~0x0c00; /* PB13 */
PBCR2 &= ~0xcc00; /* PB5 abd PB7 */
/* PB5 is "MAS enable". make it output and high */
PBIOR |= PB5;
PBDR |= PB5;
/* Set the clock line to an output */
PBIOR |= PB13;
SDA_OUTPUT;
SDA_HI;
SCL_LO;
for (i=0;i<3;i++)
i2c_stop();
}
void i2c_ack(int bit)
{
/* Here's the deal. The MAS is slow, and sometimes needs to wait
before it can receive the acknowledge. Therefore it forces the clock
low until it is ready. We need to poll the clock line until it goes
high before we release the ack. */
SCL_LO; /* Set the clock low */
if ( bit )
SDA_HI;
else
SDA_LO;
SCL_INPUT; /* Set the clock to input */
while(!SCL) /* and wait for the MAS to release it */
yield();
DELAY;
SCL_OUTPUT;
SCL_LO;
}
int i2c_getack(void)
{
int ret = 1;
/* Here's the deal. The MAS is slow, and sometimes needs to wait
before it can send the acknowledge. Therefore it forces the clock
low until it is ready. We need to poll the clock line until it goes
high before we read the ack. */
#ifndef ARCHOS_RECORDER
SDA_LO; /* First, discharge the data line */
#endif
SDA_INPUT; /* And set to input */
SCL_INPUT; /* Set the clock to input */
while(!SCL) /* and wait for the MAS to release it */
yield();
if (SDA)
/* ack failed */
ret = 0;
SCL_OUTPUT;
SCL_LO;
SDA_HI;
SDA_OUTPUT;
return ret;
}
void i2c_outb(unsigned char byte)
{
int i;
/* clock out each bit, MSB first */
for ( i=0x80; i; i>>=1 ) {
if ( i & byte )
SDA_HI;
else
SDA_LO;
SCL_HI;
SCL_LO;
}
SDA_HI;
}
unsigned char i2c_inb(int ack)
{
int i;
unsigned char byte = 0;
/* clock in each bit, MSB first */
for ( i=0x80; i; i>>=1 ) {
#ifndef ARCHOS_RECORDER
/* Tricky business. Here we discharge the data line by driving it low
and then set it to input to see if it stays low or goes high */
SDA_LO; /* First, discharge the data line */
#endif
SDA_INPUT; /* And set to input */
SCL_HI;
if ( SDA )
byte |= i;
SCL_LO;
SDA_OUTPUT;
}
i2c_ack(ack);
return byte;
}
int i2c_write(int address, unsigned char* buf, int count )
{
int i,x=0;
i2c_start();
i2c_outb(address & 0xfe);
if (i2c_getack())
{
for (i=0; i<count; i++)
{
i2c_outb(buf[i]);
if (!i2c_getack())
{
x=-2;
break;
}
}
}
else
{
debugf("i2c_write() - no ack\n");
x=-1;
}
i2c_stop();
return x;
}
int i2c_read(int address, unsigned char* buf, int count )
{
int i,x=0;
i2c_start();
i2c_outb(address | 1);
if (i2c_getack()) {
for (i=0; i<count; i++) {
buf[i] = i2c_inb(0);
}
}
else
x=-1;
i2c_stop();
return x;
}
|
