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300 baud optimisations

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This commit is contained in:
Mark Qvist 2019-04-11 16:29:32 +02:00
parent ede7b5c443
commit 73a1a28f96
2 changed files with 30 additions and 15 deletions
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23
hardware/AFSK.c
View File

@ -410,7 +410,18 @@ void AFSK_adc_isr(Afsk *afsk, int8_t currentSample) {
afsk->iirX[1] = ((int8_t)fifo_pop(&afsk->delayFifo) * currentSample) / IIR_GAIN;
afsk->iirY[0] = afsk->iirY[1];
afsk->iirY[1] = afsk->iirX[0] + afsk->iirX[1] + (afsk->iirY[0] / IIR_POLE);
#elif FILTER_CUTOFF == 155
#define IIR_GAIN 6 // Really 5.99865959
#define IIR_POLE 2 // Really Y[0] * 0.6665921828
afsk->iirX[1] = ((int8_t)fifo_pop(&afsk->delayFifo) * currentSample) / IIR_GAIN;
afsk->iirY[0] = afsk->iirY[1];
afsk->iirY[1] = afsk->iirX[0] + afsk->iirX[1] + (afsk->iirY[0] / IIR_POLE);
#elif FILTER_CUTOFF == 100
#define IIR_GAIN 9 // Really 8.763507115
#define IIR_POLE 0.77 // Really Y[0] * 0.7717808665
afsk->iirX[1] = ((int8_t)fifo_pop(&afsk->delayFifo) * currentSample) / IIR_GAIN;
afsk->iirY[0] = afsk->iirY[1];
afsk->iirY[1] = afsk->iirX[0] + afsk->iirX[1] + (afsk->iirY[0] * IIR_POLE);
#else
#error Unsupported filter cutoff!
#endif
@ -422,7 +433,12 @@ void AFSK_adc_isr(Afsk *afsk, int8_t currentSample) {
afsk->iirX[1] = ((int8_t)fifo_pop(&afsk->delayFifo) * currentSample) / IIR_GAIN;
afsk->iirY[0] = afsk->iirY[1];
afsk->iirY[1] = afsk->iirX[0] + afsk->iirX[1] + (afsk->iirY[0] / IIR_POLE);
#elif FILTER_CUTOFF == 200
#define IIR_GAIN 9 // Really 8.763507115
#define IIR_POLE 2 // Really Y[0] * 0.7717808665
afsk->iirX[1] = ((int8_t)fifo_pop(&afsk->delayFifo) * currentSample) / IIR_GAIN;
afsk->iirY[0] = afsk->iirY[1];
afsk->iirY[1] = afsk->iirX[0] + afsk->iirX[1] + ((afsk->iirY[0] / 4) * 3);
#else
#error Unsupported filter cutoff!
#endif
@ -500,7 +516,7 @@ void AFSK_adc_isr(Afsk *afsk, int8_t currentSample) {
afsk->currentPhase %= PHASE_MAX;
afsk->actualBits <<= 1;
uint8_t bits = afsk->sampledBits & 0x07;
if (bits == 0x07 || // 111
bits == 0x06 || // 110
@ -510,6 +526,7 @@ void AFSK_adc_isr(Afsk *afsk, int8_t currentSample) {
afsk->actualBits |= 1;
}
if (!hdlcParse(&afsk->hdlc, !TRANSITION_FOUND(afsk->actualBits), &afsk->rxFifo)) {
afsk->status |= 1;
if (fifo_isfull(&afsk->rxFifo)) {

22
hardware/AFSK.h
View File

@ -39,10 +39,10 @@ inline static uint8_t sinSample(uint16_t i) {
#define CPU_FREQ F_CPU
#define BITRATE 1200
#define BITRATE 300
#if BITRATE == 300
#define CONFIG_ADC_SAMPLERATE 9600UL
#define CONFIG_ADC_SAMPLERATE 4800UL
#define CONFIG_DAC_SAMPLERATE 19200UL
#define CLOCK_TICKS_PER_10_MS 96
#elif BITRATE == 1200
@ -80,7 +80,6 @@ inline static uint8_t sinSample(uint16_t i) {
#define DAC_SAMPLESPERBIT (CONFIG_DAC_SAMPLERATE / BITRATE)
#define DAC_TICKS_BETWEEN_SAMPLES ((((CPU_FREQ+FREQUENCY_CORRECTION)) / CONFIG_DAC_SAMPLERATE) - 1)
// TODO: Maybe revert to only looking at two samples
#if BITRATE == 300
#define SIGNAL_TRANSITIONED(bits) DUAL_XOR((bits), (bits) >> 2)
#elif BITRATE == 1200
@ -94,34 +93,33 @@ inline static uint8_t sinSample(uint16_t i) {
#endif
#if BITRATE == 300
// TODO: Real-world tests on which resolution is best
//#define PHASE_BITS 8
#define PHASE_BITS 4
#define PHASE_BITS 1
#else
#define PHASE_BITS 8 // Sub-sample phase counter resolution
#endif
#define PHASE_INC 1 // Nudge by above resolution for each adjustment
#define PHASE_MAX (ADC_SAMPLESPERBIT * PHASE_BITS) // Size of our phase counter
// TODO: Test which target is best in real world
// For 1200, this seems a little better
#if BITRATE == 300
#define PHASE_THRESHOLD (PHASE_MAX / 2)
#define PHASE_THRESHOLD (PHASE_MAX / 2)
#elif BITRATE == 1200
#if CONFIG_ADC_SAMPLERATE == 19200
#define PHASE_THRESHOLD (PHASE_MAX / 2)+3*PHASE_BITS // Target transition point of our phase window
#elif CONFIG_ADC_SAMPLERATE == 9600
#define PHASE_THRESHOLD (PHASE_MAX / 2) // 64 // Target transition point of our phase window
#define PHASE_THRESHOLD (PHASE_MAX / 2) // Target transition point of our phase window
#endif
#elif BITRATE == 2400
#define PHASE_THRESHOLD (PHASE_MAX / 2) // Target transition point of our phase window
#endif
#if BITRATE == 300
#define DCD_TIMEOUT_SAMPLES 512
#define DCD_MIN_COUNT 4
#define DCD_TIMEOUT_SAMPLES 256
#define DCD_MIN_COUNT 1
#elif BITRATE == 1200
#define DCD_TIMEOUT_SAMPLES CONFIG_ADC_SAMPLERATE/100
#define DCD_MIN_COUNT CONFIG_ADC_SAMPLERATE/1600
@ -139,7 +137,7 @@ inline static uint8_t sinSample(uint16_t i) {
#define MARK_FREQ 2165
#define SPACE_FREQ 3970
#elif BITRATE == 300
#define FILTER_CUTOFF 500
#define FILTER_CUTOFF 155
#define MARK_FREQ 1600
#define SPACE_FREQ 1800
#else
@ -189,7 +187,7 @@ typedef struct Afsk
#elif BITRATE == 2400
int8_t delayBuf[7 + 1];
#elif BITRATE == 300
int8_t delayBuf[16 + 1];
int8_t delayBuf[9 + 1];
#endif
FIFOBuffer rxFifo; // FIFO for received data