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fix dshot_600

This commit is contained in:
Thorsten Laux 2019-09-07 07:31:34 +02:00
parent db66284567
commit f9da3ea755
2 changed files with 52 additions and 46 deletions
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95
src/main/drivers/dshot_bitbang_decode.c
View File

@ -129,14 +129,17 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
#endif
while (endP > p) {
while (endP > p) {
do {
// Look for next positive edge. Manual loop unrolling and branch hinting to produce faster code.
if(__builtin_expect(!(p++)->value, 1) &&
__builtin_expect(!(p++)->value, 1) &&
__builtin_expect(!(p++)->value, 1) &&
__builtin_expect(!(p++)->value, 1)) {
continue;
if(__builtin_expect((p++)->value, 0) ||
__builtin_expect((p++)->value, 0) ||
__builtin_expect((p++)->value, 0) ||
__builtin_expect((p++)->value, 0)) {
break;
}
} while (endP > p);
if (endP > p) {
#ifdef DEBUG_BBDECODE
sequence[sequenceIndex++] = p - b;
@ -149,29 +152,31 @@ uint32_t decode_bb_bitband( uint16_t buffer[], uint32_t count, uint32_t bit)
value <<= len;
value |= 1 << (len - 1);
oldP = p;
break;
}
// Look for next zero edge. Manual loop unrolling and branch hinting to produce faster code.
while (endP > p) {
if (__builtin_expect((p++)->value, 1) &&
__builtin_expect((p++)->value, 1) &&
__builtin_expect((p++)->value, 1) &&
__builtin_expect((p++)->value, 1)) {
continue;
}
// Look for next zero edge. Manual loop unrolling and branch hinting to produce faster code.
do {
if (__builtin_expect(!(p++)->value, 0) ||
__builtin_expect(!(p++)->value, 0) ||
__builtin_expect(!(p++)->value, 0) ||
__builtin_expect(!(p++)->value, 0)) {
break;
}
} while (endP > p);
if (endP > p) {
#ifdef DEBUG_BBDECODE
sequence[sequenceIndex++] = p - b;
sequence[sequenceIndex++] = p - b;
#endif
// A level of length n gets decoded to a sequence of bits of
// the form 1000 with a length of (n+1) / 3 to account for 3x
// oversampling.
const int len = MAX((p - oldP + 1) / 3, 1);
bits += len;
value <<= len;
value |= 1 << (len - 1);
oldP = p;
break;
// A level of length n gets decoded to a sequence of bits of
// the form 1000 with a length of (n+1) / 3 to account for 3x
// oversampling.
const int len = MAX((p - oldP + 1) / 3, 1);
bits += len;
value <<= len;
value |= 1 << (len - 1);
oldP = p;
}
}
}
@ -243,27 +248,27 @@ FAST_CODE uint32_t decode_bb( uint16_t buffer[], uint32_t count, uint32_t bit)
sequence[sequenceIndex++] = p - buffer;
#endif
// Look for next edge. Manual loop unrolling and branch hinting to produce faster code.
while (endP > p) {
if (__builtin_expect((*p++ & mask) == lastValue, 1) &&
__builtin_expect((*p++ & mask) == lastValue, 1) &&
__builtin_expect((*p++ & mask) == lastValue, 1) &&
__builtin_expect((*p++ & mask) == lastValue, 1)) {
continue;
}
while (endP > p ) {
// Look for next edge. Manual loop unrolling and branch hinting to produce faster code.
if (__builtin_expect((*p++ & mask) != lastValue, 0) ||
__builtin_expect((*p++ & mask) != lastValue, 0) ||
__builtin_expect((*p++ & mask) != lastValue, 0) ||
__builtin_expect((*p++ & mask) != lastValue, 0)) {
if (endP > p) {
#ifdef DEBUG_BBDECODE
sequence[sequenceIndex++] = p - buffer;
sequence[sequenceIndex++] = p - buffer;
#endif
// A level of length n gets decoded to a sequence of bits of
// the form 1000 with a length of (n+1) / 3 to account for 3x
// oversampling.
const int len = MAX((p - oldP + 1) / 3,1);
bits += len;
value <<= len;
value |= 1 << (len - 1);
oldP = p;
lastValue = *(p-1) & mask;
// A level of length n gets decoded to a sequence of bits of
// the form 1000 with a length of (n+1) / 3 to account for 3x
// oversampling.
const int len = MAX((p - oldP + 1) / 3,1);
bits += len;
value <<= len;
value |= 1 << (len - 1);
oldP = p;
lastValue = *(p-1) & mask;
}
}
}
// length of last sequence has to be inferred since the last bit with inverted dshot is high

3
src/main/drivers/dshot_bitbang_impl.h
View File

@ -199,7 +199,8 @@ extern uint32_t bbOutputBuffer[MOTOR_DSHOT_BUFFER_SIZE * MAX_SUPPORTED_MOTOR_POR
// <sampling period> = 0.44us
// <slack> = 10%
// (30 + 26 + 3) / 0.44 = 134
#define DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH 134
// In some cases this was not enough, so we add 6 extra samples
#define DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH 140
extern uint16_t bbInputBuffer[DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
void bbGpioSetup(bbMotor_t *bbMotor);