Rev 2039 | Rev 2044 | Go to most recent revision | Show entire file | Ignore whitespace | Details | Blame | Last modification | View Log | RSS feed
| Rev 2039 | Rev 2041 | ||
|---|---|---|---|
| Line 78... | Line 78... | ||
| 78 | /* Get PWM from MK3MAG */ |
78 | /* Get PWM from MK3MAG */ |
| 79 | /*********************************************/ |
79 | /*********************************************/ |
| 80 | void MK3MAG_periodicTask(void) {// called every 102.4 us by timer 0 ISR |
80 | void MK3MAG_periodicTask(void) {// called every 102.4 us by timer 0 ISR |
| 81 | static uint16_t PWMCount = 0; |
81 | static uint16_t PWMCount = 0; |
| 82 | static uint16_t beepDelay = 0; |
82 | static uint16_t beepDelay = 0; |
| 83 | static uint16_t debugCounter = 0; |
83 | // static uint16_t debugCounter = 0; |
| 84 | // The pulse width varies from 1ms (0°) to 36.99ms (359.9°) |
84 | // The pulse width varies from 1ms (0°) to 36.99ms (359.9°) |
| 85 | // in other words 100us/° with a +1ms offset. |
85 | // in other words 100us/° with a +1ms offset. |
| 86 | // The signal goes low for 65ms between pulses, |
86 | // The signal goes low for 65ms between pulses, |
| 87 | // so the cycle time is 65mS + the pulse width. |
87 | // so the cycle time is 65mS + the pulse width. |
| 88 | // pwm is high |
88 | // pwm is high |
| Line 89... | Line 89... | ||
| 89 | 89 | ||
| 90 | if (debugCounter++ == 5000) { |
90 | // if (debugCounter++ == 5000) { |
| 91 | // DebugOut.Digital[0] ^= DEBUG_MK3MAG; |
91 | // DebugOut.Digital[0] ^= DEBUG_MK3MAG; |
| 92 | debugCounter = 0; |
92 | // debugCounter = 0; |
| Line 93... | Line 93... | ||
| 93 | } |
93 | // } |
| 94 | 94 | ||
| 95 | if (PINC & (1 << PINC4)) { |
95 | if (PINC & (1 << PINC4)) { |
| 96 | // If PWM signal is high increment PWM high counter |
96 | // If PWM signal is high increment PWM high counter |
| 97 | // This counter is incremented by a periode of 102.4us, |
97 | // This counter is incremented by a periode of 102.4us, |
| 98 | // i.e. the resoluton of pwm coded heading is approx. 1 deg. |
98 | // i.e. the resoluton of pwm coded heading is approx. 1 deg. |
| 99 | PWMCount++; |
99 | PWMCount++; |
| 100 | // pwm overflow? |
100 | // pwm overflow? |
| 101 | if (PWMCount > 400) { |
101 | if (PWMCount > 400) { |
| 102 | if (PWMTimeout) |
102 | if (PWMTimeout) |
| 103 | PWMTimeout--; // decrement timeout |
103 | PWMTimeout--; // decrement timeout |
| 104 | compassHeading = -1; // unknown heading |
104 | magneticHeading = -1; // unknown heading |
| 105 | PWMCount = 0; // reset PWM Counter |
105 | PWMCount = 0; // reset PWM Counter |
| 106 | } |
106 | } |
| 107 | } else { // pwm is low |
107 | } else { // pwm is low |
| 108 | // ignore pwm values values of 0 and higher than 37 ms; |
108 | // ignore pwm values values of 0 and higher than 37 ms; |
| 109 | if ((PWMCount) && (PWMCount < 362)) { // 362 * 102.4us = 37.0688 ms |
109 | if ((PWMCount) && (PWMCount < 362)) { // 362 * 102.4us = 37.0688 ms |
| 110 | if (PWMCount < 10) |
110 | if (PWMCount < 10) |
| 111 | compassHeading = 0; |
111 | magneticHeading = 0; |
| 112 | else { |
112 | else { |
| 113 | compassHeading = ((uint32_t) (PWMCount - 10) * 1049L) / 1024; // correct timebase and offset |
113 | magneticHeading = ((uint32_t) (PWMCount - 10) * 1049L) / 1024; // correct timebase and offset |
| 114 | //DebugOut.Digital[1] ^= DEBUG_MK3MAG; // correct signal recd. |
114 | //DebugOut.Digital[1] ^= DEBUG_MK3MAG; // correct signal recd. |
| 115 | } |
115 | } |
| 116 | /* |
116 | /* |
| Line 124... | Line 124... | ||
| 124 | PWMTimeout = 12; // if 12 periodes long no valid PWM was detected the data are invalid |
124 | PWMTimeout = 12; // if 12 periodes long no valid PWM was detected the data are invalid |
| 125 | // 12 * 362 counts * 102.4 us |
125 | // 12 * 362 counts * 102.4 us |
| 126 | } |
126 | } |
| 127 | PWMCount = 0; // reset pwm counter |
127 | PWMCount = 0; // reset pwm counter |
| 128 | } |
128 | } |
| - | 129 | ||
| 129 | if (!PWMTimeout) { |
130 | if (!PWMTimeout) { |
| 130 | if (checkDelay(beepDelay)) { |
131 | if (checkDelay(beepDelay)) { |
| 131 | if (!beepTime) |
132 | if (!beepTime) |
| 132 | beepTime = 100; // make noise with 10Hz to signal the compass problem |
133 | beep(100); // make noise with 10Hz to signal the compass problem |
| 133 | beepDelay = setDelay(100); |
134 | beepDelay = setDelay(100); |
| 134 | } |
135 | } |
| 135 | } |
136 | } |
| 136 | } |
137 | } |