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1 | /* $Id: ircontrol.c,v 1.6 2010/07/10 07:36:28 simimeie Exp $ |
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2 | * Functions for the infrared receiver |
3 | * |
4 | * The infrared receiver is connected to PB0 / PCINT0. |
5 | */ |
6 | |
7 | #include <avr/io.h> |
8 | #include <avr/interrupt.h> |
9 | #include "ircontrol.h" |
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10 | #include "timers.h" |
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11 | #include "console.h" |
12 | |
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13 | /* NOTE1: Note that the signal we get from the sensor is inverted. If we |
14 | * read a zero, it means there was infrared on, if we read a one, infrared |
15 | * is off. |
16 | * NOTE2: Only NEC is implemented here right now, because MY remote uses |
17 | * that protocol. However, there may be references to RC5 because I had |
18 | * already thought about that and just left them for possible future use. */ |
19 | |
20 | /* For RC5, one bit length is 1778 us, when it toggles we see half |
21 | * of it, i.e. 889 us. |
22 | * that equals around 7100 cpu cycles at 8 MHz. */ |
23 | #define RC5HALFLENINCYCLES ((CPUFREQ * 889UL) / 1000000UL) |
24 | |
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25 | /* Source for most of this was the following nice page with illustrations |
26 | * and all that: http://www.sbprojects.com/knowledge/ir/nec.htm |
27 | * For NEC, we start with a 9000 us pulse, then 4500 us silence. |
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28 | * Then the bits follow: |
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29 | * a 1 is a 560 us pulse followed by 1690 us of silence (=2250 us total). |
30 | * a 0 is a 560 us pulse followed by 560 us of silence (=1120 us total). |
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31 | * These values equal the following cpu cycle counts: |
32 | * 9000 us = 72000 cc, 4500 us = 36000 cc, 560 us = 4480, 1690 us = 13520 cc |
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33 | * When the key stays pressed, it is not resubmitted, but instead a special |
34 | * "repeat" code is sent. That is: 9000 us pulse, 2250 us silence, 560 us |
35 | * pulse. |
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36 | */ |
37 | #define NECSTARTLEN1 ((CPUFREQ * 9UL) / 1000UL) |
38 | #define NECSTARTLEN2 ((CPUFREQ * 45UL) / 10000UL) |
39 | #define NECPULSELEN ((CPUFREQ * 56UL) / 100000UL) |
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40 | #define NECZEROLEN ((CPUFREQ * 112UL) / 100000UL) |
41 | #define NECONELEN ((CPUFREQ * 225UL) / 100000UL) |
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42 | #define NECREPEATLEN ((CPUFREQ * 225UL) / 100000UL) |
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43 | |
44 | /* the NEC code contains 4 bytes, sent with LSB first: |
45 | * 0+1 are either the "extended address" or "address and inverted address". |
46 | * 2 is the command code |
47 | * 3 is the inverted command code |
48 | */ |
49 | |
50 | static struct timestamp last0irqts; |
51 | static struct timestamp last1irqts; |
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52 | static uint8_t lastpin = 0xff; |
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53 | static uint8_t codebytes[4]; |
54 | static uint8_t curcodebit = 0xff; |
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55 | static uint8_t lastcommand = 0xff; |
56 | static uint8_t repeatcommand = 0xff; |
57 | static uint16_t repeatticks = 0; |
58 | /* Repeat after this many ticks (70 = 0.5s) */ |
59 | #define REPEATAFTERTICKS 100 |
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60 | |
61 | /* some example codes |
62 | root@moodlight# !NSB! 11111111 00001000 11011111 00100000 (r) |
63 | root@moodlight# !NSB! 11111111 00001000 01011111 10100000 (g) |
64 | root@moodlight# !NSB! 11111111 00001000 10011111 01100000 (b) |
65 | root@moodlight# !NSB! 11111111 00001000 00011111 11100000 (w) |
66 | */ |
67 | |
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68 | ISR(PCINT0_vect) { |
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69 | uint8_t v; |
70 | struct timestamp curirqts; |
71 | uint32_t ts1diff; /* distance from last 1 */ |
72 | uint32_t ts0diff; /* distance from last 0 */ |
73 | |
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74 | v = PINB & _BV(0); |
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75 | if (v == lastpin) { /* No change visible - spurious interrupt */ |
76 | return; |
77 | } |
78 | curirqts = gettimestamp_noirq(); |
79 | ts1diff = ((uint32_t)curirqts.ticks << 16) + curirqts.partticks; |
80 | ts0diff = ts1diff; |
81 | ts1diff -= ((uint32_t)last1irqts.ticks << 16) + last1irqts.partticks; |
82 | ts0diff -= ((uint32_t)last0irqts.ticks << 16) + last0irqts.partticks; |
83 | if (v) { /* Infrared just went away! */ |
84 | if ((ts1diff >= (( 8 * NECSTARTLEN1) / 10)) |
85 | && (ts1diff <= ((12 * NECSTARTLEN1) / 10))) { |
86 | /* NEC start bit */ |
87 | /* console_printpgm_P(PSTR("!NSB!")); */ |
88 | curcodebit = 0xfe; /* Wait for second part of start sequence */ |
89 | } else { |
90 | if (curcodebit <= 32) { /* We're in a decoding attempt, so */ |
91 | /* Check pulse length */ |
92 | if ((ts1diff < (( 8 * NECPULSELEN) / 10)) |
93 | || (ts1diff > ((12 * NECPULSELEN) / 10))) { |
94 | /* WRONG */ |
95 | curcodebit = 0xff; |
96 | } |
97 | } |
98 | if (curcodebit == 32) { |
99 | if (codebytes[2] != (codebytes[3] ^ 0xff)) { |
100 | console_printpgm_P(PSTR("!CRC!")); |
101 | } else { |
102 | /* Successful decode! */ |
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103 | lastcommand = codebytes[2]; |
104 | repeatcommand = codebytes[2]; |
105 | repeatticks = curirqts.ticks; |
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106 | console_printpgm_P(PSTR(" DEC>")); |
107 | console_printhex8(codebytes[0]); |
108 | console_printhex8(codebytes[1]); |
109 | console_printhex8(codebytes[2]); |
110 | console_printhex8(codebytes[3]); |
111 | } |
112 | } |
113 | } |
114 | last0irqts = curirqts; |
115 | } else { /* Infrared went on */ |
116 | if ((ts1diff >= (( 8 * NECZEROLEN) / 10)) |
117 | && (ts1diff <= ((12 * NECZEROLEN) / 10))) { |
118 | /* console_printpgm_P(PSTR("0")); */ |
119 | if (curcodebit < 32) { |
120 | curcodebit++; |
121 | } |
122 | } else if ((ts1diff >= (( 8 * NECONELEN) / 10)) |
123 | && (ts1diff <= ((12 * NECONELEN) / 10))) { |
124 | /* console_printpgm_P(PSTR("1")); */ |
125 | if (curcodebit < 32) { |
126 | codebytes[curcodebit >> 3] |= (1 << (curcodebit & 0x07)); |
127 | curcodebit++; |
128 | } else { |
129 | curcodebit = 0xff; |
130 | } |
131 | } else if ((ts0diff >= (( 8 * NECSTARTLEN2) / 10)) |
132 | && (ts0diff <= ((12 * NECSTARTLEN2) / 10))) { |
133 | if (curcodebit == 0xfe) { /* voila, correct start sequence */ |
134 | curcodebit = 0; |
135 | codebytes[0] = codebytes[1] = codebytes[2] = codebytes[3] = 0; |
136 | } |
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137 | } else if ((ts0diff >= (( 8 * NECREPEATLEN) / 10)) |
138 | && (ts0diff <= ((12 * NECREPEATLEN) / 10))) { |
139 | if (curcodebit == 0xfe) { |
140 | console_printpgm_P(PSTR(".REP.")); |
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141 | if ((curirqts.ticks - repeatticks) > REPEATAFTERTICKS) { |
142 | if ((repeatcommand == 0x00) || (repeatcommand == 0x01)) { |
143 | /* Only the up/down arrows are allowed to be repeated */ |
144 | lastcommand = repeatcommand; |
145 | } |
146 | } |
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147 | } |
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148 | } |
149 | last1irqts = curirqts; |
150 | } |
151 | #if 0 |
152 | console_printpgm_P(PSTR("!")); |
153 | console_printhex8(tsdiff >> 24); |
154 | console_printhex8(tsdiff >> 16); |
155 | console_printhex8(tsdiff >> 8); |
156 | console_printhex8(tsdiff >> 0); |
157 | console_printpgm_P(PSTR("!")); |
158 | #endif |
159 | #if 0 |
160 | if (tsdiff > ((24 * HALFRC5LENINCYCLES) / 10)) { |
161 | /* Start of new transmission */ |
162 | console_printpgm_P(PSTR("!1[")); |
163 | console_printhex8(v); |
164 | lastbit = 1; |
165 | } else if (tsdiff > ((15 * HALFRC5LENINCYCLES) / 10)) { |
166 | /* Different bit than last time */ |
167 | lastbit = !lastbit; |
168 | if (lastbit) { |
169 | console_printpgm_P(PSTR("1")); |
170 | } else { |
171 | console_printpgm_P(PSTR("0")); |
172 | } |
173 | } else if ((tsdiff < ((15 * HALFRC5LENINCYCLES) / 10)) |
174 | && (tsdiff > (( 5 * HALFRC5LENINCYCLES) / 10))) { |
175 | /* Same bit as last time */ |
176 | if (lastbit) { |
177 | console_printpgm_P(PSTR("1")); |
178 | } else { |
179 | console_printpgm_P(PSTR("0")); |
180 | } |
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181 | } |
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182 | #endif |
183 | lastpin = v; |
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184 | } |
185 | |
186 | void ircontrol_init(void) |
187 | { |
188 | /* Activate pullup */ |
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189 | PORTB |= _BV(0); |
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190 | /* enable PCINT0 */ |
191 | PCICR |= _BV(PCIE0); |
192 | /* Enable pin change interrupt 0 (=PB0) in pcint0 */ |
193 | PCMSK0 |= _BV(PCINT0); |
194 | } |
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195 | |
196 | uint8_t ircontrol_getlastcommand(void) |
197 | { |
198 | uint8_t res; |
199 | res = lastcommand; |
200 | lastcommand = 0xff; |
201 | return res; |
202 | } |