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Mark Qvist 2018-12-31 13:24:28 +01:00
parent 56bed68143
commit 874689c602
4 changed files with 109 additions and 51 deletions
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60
hardware/AFSK.h
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@ -11,7 +11,7 @@
#include "protocol/HDLC.h"
#define SIN_LEN 512
static const uint8_t sin_table[] PROGMEM =
static const uint8_t sine_table[] =
{
128, 129, 131, 132, 134, 135, 137, 138, 140, 142, 143, 145, 146, 148, 149, 151,
152, 154, 155, 157, 158, 160, 162, 163, 165, 166, 167, 169, 170, 172, 173, 175,
@ -26,7 +26,7 @@ static const uint8_t sin_table[] PROGMEM =
inline static uint8_t sinSample(uint16_t i) {
uint16_t newI = i % (SIN_LEN/2);
newI = (newI >= (SIN_LEN/4)) ? (SIN_LEN/2 - newI -1) : newI;
uint8_t sine = pgm_read_byte(&sin_table[newI]);
uint8_t sine = sine_table[newI];
return (i >= (SIN_LEN/2)) ? (255 - sine) : sine;
}
@ -34,12 +34,8 @@ inline static uint8_t sinSample(uint16_t i) {
#define SWITCH_TONE(inc) (((inc) == MARK_INC) ? SPACE_INC : MARK_INC)
#define BITS_DIFFER(bits1, bits2) (((bits1)^(bits2)) & 0x01)
#define TRANSITION_FOUND(bits) BITS_DIFFER((bits), (bits) >> 1)
// TODO: Maybe revert to only looking at two samples
#define DUAL_XOR(bits1, bits2) ((((bits1)^(bits2)) & 0x03) == 0x03)
#define QUAD_XOR(bits1, bits2) ((((bits1)^(bits2)) & 0x0F) == 0x0F)
#define SIGNAL_TRANSITIONED(bits) QUAD_XOR((bits), (bits) >> 4)
// #define SIGNAL_TRANSITIONED(bits) DUAL_XOR((bits), (bits) >> 2)
#define CPU_FREQ F_CPU
@ -47,22 +43,37 @@ inline static uint8_t sinSample(uint16_t i) {
#define CONFIG_AFSK_TX_BUFLEN CONFIG_SAMPLERATE/150
#define CONFIG_AFSK_RXTIMEOUT 0
#define CONFIG_AFSK_TXWAIT 0UL
#define CONFIG_AFSK_PREAMBLE_LEN 350UL
#define CONFIG_AFSK_TRAILER_LEN 50UL
#define CONFIG_AFSK_PREAMBLE_LEN 450UL
#define CONFIG_AFSK_TRAILER_LEN 10UL
#define BIT_STUFF_LEN 5
#define BITRATE 1200
#define SAMPLESPERBIT (CONFIG_SAMPLERATE / BITRATE)
#define TICKS_BETWEEN_SAMPLES ((((CPU_FREQ+FREQUENCY_CORRECTION)) / CONFIG_SAMPLERATE) - 1)
// TODO: Calculate based on sample rate [Done?]
#define PHASE_BITS 8 // 8 // Sub-sample phase counter resolution
#define PHASE_INC 1 // 1 // Nudge by above resolution for each adjustment
// TODO: Maybe revert to only looking at two samples
#if BITRATE == 1200
#define SIGNAL_TRANSITIONED(bits) QUAD_XOR((bits), (bits) >> 4)
#elif BITRATE == 2400
#define SIGNAL_TRANSITIONED(bits) DUAL_XOR((bits), (bits) >> 2)
#endif
// TODO: Calculate based on sample rate [Done?]
#define PHASE_BITS 8 // Sub-sample phase counter resolution
#define PHASE_INC 1 // Nudge by above resolution for each adjustment
#define PHASE_MAX (SAMPLESPERBIT * PHASE_BITS) // Size of our phase counter
#define PHASE_MAX (SAMPLESPERBIT * PHASE_BITS) // 128 // Size of our phase counter
// TODO: Test which target is best in real world
#define PHASE_THRESHOLD (PHASE_MAX / 2)+3*PHASE_BITS // Target transition point of our phase window
//#define PHASE_THRESHOLD (PHASE_MAX / 2) // 64 // Target transition point of our phase window
// For 1200, this seems a little better
#if BITRATE == 1200
#define PHASE_THRESHOLD (PHASE_MAX / 2)+3*PHASE_BITS // Target transition point of our phase window
//#define PHASE_THRESHOLD (PHASE_MAX / 2) // 64 // Target transition point of our phase window
#elif BITRATE == 2400
#define PHASE_THRESHOLD (PHASE_MAX / 2)+14 // Target transition point of our phase window
#endif
#define DCD_TIMEOUT_SAMPLES CONFIG_SAMPLERATE/100
#define DCD_MIN_COUNT CONFIG_SAMPLERATE/1600
@ -72,6 +83,16 @@ inline static uint8_t sinSample(uint16_t i) {
#define FILTER_CUTOFF 600
#define MARK_FREQ 1200
#define SPACE_FREQ 2200
#elif BITRATE == 2400
#define FILTER_CUTOFF 772
// #define MARK_FREQ 2165
// #define SPACE_FREQ 3970
#define MARK_FREQ 2200
#define SPACE_FREQ 4000
#elif BITRATE == 300
#define FILTER_CUTOFF 600
#define MARK_FREQ 1600
#define SPACE_FREQ 1800
#else
#error Unsupported bitrate!
#endif
@ -117,7 +138,12 @@ typedef struct Afsk
// Demodulation values
FIFOBuffer delayFifo; // Delayed FIFO for frequency discrimination
int8_t delayBuf[SAMPLESPERBIT / 2 + 1]; // Actual data storage for said FIFO
#if BITRATE == 1200
int8_t delayBuf[SAMPLESPERBIT / 2 + 1]; // Actual data storage for said FIFO
//int8_t delayBuf[3 + 1]; // Actual data storage for said FIFO
#elif BITRATE == 2400
int8_t delayBuf[7 + 1]; // Actual data storage for said FIFO
#endif
FIFOBuffer rxFifo; // FIFO for received data
uint8_t rxBuf[CONFIG_AFSK_RX_BUFLEN]; // Actual data storage for said FIFO
@ -128,7 +154,9 @@ typedef struct Afsk
#if SAMPLESPERBIT < 17
uint16_t sampledBits; // Bits sampled by the demodulator (at ADC speed)
#else
#error Not enough space in sampledBits variable!
// TODO: Enable error and set up correct size buffers
uint16_t sampledBits;
//#error Not enough space in sampledBits variable!
#endif
int16_t currentPhase; // Current phase of the demodulator
uint8_t actualBits; // Actual found bits at correct bitrate