Git-Mirrors/OpenModem
1
0
Fork 0
mirror of https://github.com/markqvist/OpenModem.git synced 2025-06-04 12:59:02 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Moved to 20MHz clock, 2400 baud implemented

Browse source
This commit is contained in:
Mark Qvist 2019-01-01 20:34:02 +01:00
parent 874689c602
commit 43724186c9
7 changed files with 48 additions and 36 deletions
Download patch file Download diff file Expand all files Collapse all files

50
hardware/AFSK.h
View file

@ -7,7 +7,6 @@
#include <stdio.h>
#include <avr/pgmspace.h>
#include "util/FIFO.h"
#include "util/time.h"
#include "protocol/HDLC.h"
#define SIN_LEN 512
@ -43,18 +42,29 @@ 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 450UL
#define CONFIG_AFSK_TRAILER_LEN 10UL
#define CONFIG_AFSK_PREAMBLE_LEN 150UL
#define CONFIG_AFSK_TRAILER_LEN 25UL
#define BIT_STUFF_LEN 5
#define BITRATE 1200
#define BITRATE 2400
#if BITRATE == 1200
#define CONFIG_SAMPLERATE 9600UL
#elif BITRATE == 2400
#define CONFIG_SAMPLERATE 19200UL
#endif
#define SAMPLESPERBIT (CONFIG_SAMPLERATE / BITRATE)
#define TICKS_BETWEEN_SAMPLES ((((CPU_FREQ+FREQUENCY_CORRECTION)) / CONFIG_SAMPLERATE) - 1)
// TODO: Maybe revert to only looking at two samples
#if BITRATE == 1200
#define SIGNAL_TRANSITIONED(bits) QUAD_XOR((bits), (bits) >> 4)
#if CONFIG_SAMPLERATE == 19200
#define SIGNAL_TRANSITIONED(bits) QUAD_XOR((bits), (bits) >> 4)
#elif CONFIG_SAMPLERATE == 9600
#define SIGNAL_TRANSITIONED(bits) DUAL_XOR((bits), (bits) >> 2)
#endif
#elif BITRATE == 2400
#define SIGNAL_TRANSITIONED(bits) DUAL_XOR((bits), (bits) >> 2)
#endif
@ -68,10 +78,13 @@ inline static uint8_t sinSample(uint16_t i) {
// TODO: Test which target is best in real world
// 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
#if CONFIG_SAMPLERATE == 19200
#define PHASE_THRESHOLD (PHASE_MAX / 2)+3*PHASE_BITS // Target transition point of our phase window
#elif CONFIG_SAMPLERATE == 9600
#define PHASE_THRESHOLD (PHASE_MAX / 2) // 64 // Target transition point of our phase window
#endif
#elif BITRATE == 2400
#define PHASE_THRESHOLD (PHASE_MAX / 2)+14 // Target transition point of our phase window
#define PHASE_THRESHOLD (PHASE_MAX / 2) // Target transition point of our phase window
#endif
@ -80,15 +93,17 @@ inline static uint8_t sinSample(uint16_t i) {
// TODO: Revamp filtering
#if BITRATE == 1200
#define FILTER_CUTOFF 600
#define FILTER_CUTOFF 500
#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
// TODO: Determine best filter cutoff
// #define FILTER_CUTOFF 772
#define FILTER_CUTOFF 1000
#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
@ -139,8 +154,11 @@ typedef struct Afsk
// Demodulation values
FIFOBuffer delayFifo; // Delayed FIFO for frequency discrimination
#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
#if CONFIG_SAMPLERATE == 19200
int8_t delayBuf[SAMPLESPERBIT / 2 + 1]; // Actual data storage for said FIFO
#elif CONFIG_SAMPLERATE == 9600
int8_t delayBuf[SAMPLESPERBIT / 2 + 1]; // Actual data storage for said FIFO
#endif
#elif BITRATE == 2400
int8_t delayBuf[7 + 1]; // Actual data storage for said FIFO
#endif