source: trunk/FirmwareFX2/spi.c@ 78

Last change on this file since 78 was 4, checked in by demin, 15 years ago

initial commit
File size: 4.3 KB
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1/* -*- c++ -*- */
2/*
3 * Copyright 2004,2006 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
10 * any later version.
11 *
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
21 *
22 *
23 * Modified by Matthias P. Braendli
24*/
25
26#include "spi.h"
27#include "fx2regs.h"
28#include "fx2utils.h"
29
30void
31init_spi (void)
32{
33 SPI |= bmSS; /* active low, disable slave */
34 bitS_OUT = 0; /* idle state has CLK = 0 */
35}
36
37unsigned char
38spi_read (unsigned char header_hi, unsigned char header_lo,
39 unsigned char format, unsigned char address,
40 xdata unsigned char *buf, unsigned char len)
41{
42 SPI &= ~bmSS; // enable slave select
43
44 spi_write_byte_msb(address); // send destination periph address
45
46 switch (format & SPI_FMT_HDR_MASK){
47 case SPI_FMT_HDR_0:
48 break;
49 case SPI_FMT_HDR_1:
50 spi_write_byte_msb (header_lo);
51 break;
52 case SPI_FMT_HDR_2:
53 spi_write_byte_msb (header_hi);
54 spi_write_byte_msb (header_lo);
55 break;
56 default:
57 return 1; // error
58 }
59 if (len != 0)
60 spi_read_bytes_msb (buf, len);
61
62
63 SPI |= bmSS; /* active low, disable slave */
64
65 return 0; // success
66}
67
68
69unsigned char
70spi_write (unsigned char header_hi, unsigned char header_lo,
71 unsigned char format, unsigned char address,
72 const xdata unsigned char *buf, unsigned char len)
73{
74 SPI &= ~bmSS; // enable slave select
75
76 spi_write_byte_msb(address); // send destination periph address
77
78 switch (format & SPI_FMT_HDR_MASK){
79 case SPI_FMT_HDR_0:
80 break;
81 case SPI_FMT_HDR_1:
82 spi_write_byte_msb (header_lo);
83 break;
84 case SPI_FMT_HDR_2:
85 spi_write_byte_msb (header_hi);
86 spi_write_byte_msb (header_lo);
87 break;
88 default:
89 SPI |= bmSS; /* active low, disable slave */
90 return 1; // error
91 }
92
93 if (len != 0)
94 spi_write_bytes_msb (buf, len);
95
96 SPI |= bmSS; /* active low, disable slave */
97 return 0; // success
98}
99
100// ----------------------------------------------------------------
101
102void
103spi_write_byte_msb (unsigned char v)
104{
105 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
106 bitS_OUT = v & 0x1;
107 bitS_CLK = 1;
108 bitS_CLK = 0;
109
110 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
111 bitS_OUT = v & 0x1;
112 bitS_CLK = 1;
113 bitS_CLK = 0;
114
115 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
116 bitS_OUT = v & 0x1;
117 bitS_CLK = 1;
118 bitS_CLK = 0;
119
120 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
121 bitS_OUT = v & 0x1;
122 bitS_CLK = 1;
123 bitS_CLK = 0;
124
125 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
126 bitS_OUT = v & 0x1;
127 bitS_CLK = 1;
128 bitS_CLK = 0;
129
130 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
131 bitS_OUT = v & 0x1;
132 bitS_CLK = 1;
133 bitS_CLK = 0;
134
135 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
136 bitS_OUT = v & 0x1;
137 bitS_CLK = 1;
138 bitS_CLK = 0;
139
140 v = (v << 1) | (v >> 7); // rotate left (MSB into bottom bit)
141 bitS_OUT = v & 0x1;
142 bitS_CLK = 1;
143 bitS_CLK = 0;
144}
145
146void
147spi_write_bytes_msb (const xdata unsigned char *buf, unsigned char len)
148{
149 while (len-- != 0){
150 spi_write_byte_msb (*buf++);
151 }
152}
153
154unsigned char
155spi_read_byte_msb (void) _naked
156{
157 _asm
158 clr a
159
160 setb _bitS_CLK
161 mov c, _bitS_IN
162 rlc a
163 clr _bitS_CLK
164
165 setb _bitS_CLK
166 mov c, _bitS_IN
167 rlc a
168 clr _bitS_CLK
169
170 setb _bitS_CLK
171 mov c, _bitS_IN
172 rlc a
173 clr _bitS_CLK
174
175 setb _bitS_CLK
176 mov c, _bitS_IN
177 rlc a
178 clr _bitS_CLK
179
180 setb _bitS_CLK
181 mov c, _bitS_IN
182 rlc a
183 clr _bitS_CLK
184
185 setb _bitS_CLK
186 mov c, _bitS_IN
187 rlc a
188 clr _bitS_CLK
189
190 setb _bitS_CLK
191 mov c, _bitS_IN
192 rlc a
193 clr _bitS_CLK
194
195 setb _bitS_CLK
196 mov c, _bitS_IN
197 rlc a
198 clr _bitS_CLK
199
200 mov dpl,a
201 ret
202 _endasm;
203}
204
205void
206spi_read_bytes_msb (xdata unsigned char *buf, unsigned char len)
207{
208 while (len-- != 0){
209 *buf++ = spi_read_byte_msb ();
210 }
211}
212
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