Revision 86b48573
| ID | 86b48573fdb86a6acb04eb3a1e9de80b22f0791e |
Range sensors work now! :D
| scout_avr/src/range.cpp | ||
|---|---|---|
| 14 | 14 |
* 37.5ms * 8 MHz / 8 prescaler = 37500 max wait |
| 15 | 15 |
* 37.5ms * 16 MHz / 8 prescaler = problem |
| 16 | 16 |
* 37.5ms * 16 MHz / 64 prescaler = 9375 max wait |
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* 147us/in * 16 MHz / 64 prescaler = 1.44685039 ticks / mm |
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*/ |
| 18 | 19 |
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| 19 | 20 |
struct range_t {
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unsigned int start; // timer value on rising edge |
| 21 | 22 |
unsigned int value; // last measured range |
| 22 |
char started; |
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char done; |
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char busy; |
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} volatile range[2]; |
| 25 | 25 |
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static void on_edge(int which) |
| ... | ... | |
| 40 | 40 |
if (int_high) |
| 41 | 41 |
{
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range[which].start = time; |
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range[which].started = 1;
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range[which].busy = 1;
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} |
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else |
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{
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// if timer overflowed since start, this arithmetic should still work out |
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range[which].value = time - range[which].start; |
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range[which].done = 1;
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range[which].busy = 0;
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} |
| 51 | 51 |
} |
| 52 | 52 |
|
| ... | ... | |
| 83 | 83 |
for (i = 0; i < 2; i++) |
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{
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range[i].value = RANGE_ERR; |
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range[i].started = 0; |
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range[i].done = 0; |
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range[i].busy = 0; |
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} |
| 89 | 88 |
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// TODO ensure that one interrupt won't be delayed because of the other |
| 91 | 90 |
PORT_SONAR_TX |= _BV(P_SONAR_TX); |
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_delay_ms(1);
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_delay_ms(40);
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PORT_SONAR_TX &= ~ _BV(P_SONAR_TX); |
| 94 | 93 |
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for (i = 0; i < 2; i++) |
| 96 | 95 |
{
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if (range[i].started) {
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while (!range[i].done) {}
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values[i] = range[i].value; |
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} |
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while (range[i].busy) {}
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values[i] = range[i].value; |
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| 101 | 98 |
} |
| 102 | 99 |
} |
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