summaryrefslogtreecommitdiff
path: root/software/ihu/ttx.inc
blob: 8fa147994834fa17dcdc9a3f307825fd412ea2b0 (plain) (blame)
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
  ;;
  ;;  mur.sat
  ;;
  ;;  Somewhen in the year 2012, mur.at will have a nano satellite launched
  ;;  into a low earth orbit (310 km above the surface of our planet). The
  ;;  satellite itself is a TubeSat personal satellite kit, developed and
  ;;  launched by interorbital systems. mur.sat is a joint venture of mur.at,
  ;;  ESC im Labor and realraum.
  ;;
  ;;  Please visit the project hompage at sat.mur.at for further information.
  ;; 
  ;;
  ;;  Copyright (C) 2011 Christian Pointner <equinox@mur.at>
  ;;                         
  ;;  This file is part of mur.sat.
  ;;
  ;;  mur.sat is free software: you can redistribute it and/or modify
  ;;  it under the terms of the GNU General Public License as published by
  ;;  the Free Software Foundation, either version 3 of the License, or
  ;;  any later version.
  ;;
  ;;  mur.sat is distributed in the hope that it will be useful,
  ;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
  ;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  ;;  GNU General Public License for more details.
  ;;
  ;;  You should have received a copy of the GNU General Public License
  ;;  along with mur.sat. If not, see <http://www.gnu.org/licenses/>.
  ;;

  ;; -------------------------------------
ttx_send_byte
  bsf       STATUS,RP0
  bcf       TTX_SDA
  bcf       STATUS,RP0
  movwf     TTX_BYTE
  xorwf     TTX_CSUM,f
  movlw     .8
  movwf     TTX_BIT_CNT
ttx_send_next_bit
  btfsc     TTX_BYTE,7
  bsf       TTX_SDA
  btfss     TTX_BYTE,7
  bcf       TTX_SDA
  bsf       TTX_SCL
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  bcf       TTX_SCL
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  rlf       TTX_BYTE,f
  decfsz    TTX_BIT_CNT,f
  goto      ttx_send_next_bit
  bsf       STATUS,RP0
  bsf       TTX_SDA
  bcf       STATUS,RP0
  return

  ;; -------------------------------------
ttx_recv_byte
  movlw     .8
  movwf     TTX_BIT_CNT
ttx_recv_next_bit
  bsf       TTX_SCL
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  bcf       TTX_SCL
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  rlf       TTX_BYTE,f
  btfsc     TTX_SDA
  bsf       TTX_BYTE,0
  btfss     TTX_SDA
  bcf       TTX_BYTE,0
  decfsz    TTX_BIT_CNT,f
  goto      ttx_recv_next_bit
  return
    
  ;; -------------------------------------
ttx_break
  movlw     .13
  movwf     TTX_BIT_CNT
ttx_wait_octet
  decfsz    TTX_BIT_CNT,f
  goto      ttx_wait_octet
  return
  
  ;; -------------------------------------
ttx_send_frame
  movwf     TTX_BYTE
  andlw     b'00001111'
  movwf     TTX_BYTE_CNT
  bsf       TTX_SCL
  movlw     .3
  bcf       TTX_SCL
  call      wait_ms

  clrf      TTX_CSUM
  movf      TTX_BYTE,w
  call      ttx_send_byte

  movf      TTX_BYTE_CNT,f
  btfsc     STATUS,Z
  goto      ttx_get_csum

ttx_next_byte
  call      ttx_break
  movf      INDF,w
  call      ttx_send_byte

  incf      FSR,f
  decfsz    TTX_BYTE_CNT,f
  goto      ttx_next_byte

ttx_get_csum
  return

  call      ttx_break
  call      ttx_recv_byte
  movf      TTX_BYTE,w
  xorwf     TTX_CSUM,w
  btfss     STATUS,Z
  goto      ttx_csum_error
  retlw     .0

ttx_csum_error
  retlw     .1

  ;; -------------------------------------
ttx_send
  call      ttx_send_frame
  return
  
  movwf     TTX_BYTE
  movwf     TXREG
  call      ttx_break

  bsf       TTX_SDA
  bsf       STATUS,RP0
  bcf       TTX_SDA
  bcf       STATUS,RP0
  btfss     TTX_BYTE,0
  bcf       TTX_SDA
  bsf       TTX_SCL
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  bcf       TTX_SCL
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  nop
  bsf       STATUS,RP0
  bsf       TTX_SDA
  bcf       STATUS,RP0
  movf      TTX_BYTE,w
  return
  ;; -------------------------------------