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Added wspr encoder for AVR

wspr-beacon
Sebastian 2 years ago
parent
commit
75804382b4
3 changed files with 161 additions and 33 deletions
  1. +3
    -32
      firmware/include/wspr.h
  2. +4
    -1
      firmware/main.c
  3. +154
    -0
      firmware/wspr.c

+ 3
- 32
firmware/include/wspr.h View File

@ -6,40 +6,11 @@
#include "si5351.h"
#define WSPR_LENGTH 162
// For PLL with 800MHz
static const struct si5351_params WSPR_SYMBOLS[4] = {
// 7040100.000000: 113 + 44687 / 70401
// actual: 7040100.000000
{14033, 17455, 70401},
// 7040101.464844: 113 + 447801 / 705503
// actual: 7040101.464844
{14033, 172785, 705503},
// 7040102.929688: 113 + 38515 / 60682
// actual: 7040102.929688
{14033, 14678, 60682},
// 7040104.394531: 113 + 123233 / 194166
// actual: 7040104.394531
{14033, 46378, 194166},
};
static const uint8_t WSPR_LENGTH = 162;
static const uint16_t WSPR_PERIOD = 683;
// DL1SSK at JN39we
static uint8_t default_wspr_msg[162] = {
1, 1, 0, 0, 2, 0, 0, 2, 1, 0, 0, 0, 1, 3, 3, 2, 2, 2, 3, 2, 0, 1, 0, 3, 1, 1, 1, 0, 2,
2, 0, 2, 2, 0, 3, 0, 0, 1, 0, 3, 2, 0, 0, 0, 0, 0, 3, 0, 1, 1, 0, 0, 3, 1, 2, 1, 0, 2,
2, 3, 1, 2, 1, 2, 2, 2, 2, 3, 3, 2, 1, 2, 1, 2, 1, 2, 3, 2, 0, 3, 2, 0, 1, 0, 3, 3, 0,
2, 2, 1, 1, 2, 1, 0, 1, 0, 2, 0, 1, 2, 2, 2, 0, 0, 3, 2, 2, 3, 0, 0, 1, 3, 3, 2, 3, 3,
0, 2, 3, 1, 2, 1, 0, 2, 2, 3, 3, 3, 0, 2, 2, 0, 2, 1, 2, 1, 2, 0, 1, 3, 0, 0, 0, 0, 0,
2, 0, 3, 1, 0, 1, 2, 3, 1, 2, 2, 2, 1, 1, 0, 0, 2
};
void wspr_encode(char *call, char *loc, uint8_t power, uint8_t *buffer);
void wspr_transmit(enum si5351_multisynth synth, uint8_t *msg);
#endif

+ 4
- 1
firmware/main.c View File

@ -19,7 +19,10 @@ int main(void) {
//si5351_ms_write_params(SI5351_MS0, WSPR_SYMBOLS[3]);
wspr_transmit(SI5351_MS0, default_wspr_msg);
uint8_t wspr_buffer[WSPR_LENGTH];
wspr_encode("DL1SSK", "JN39", 27, wspr_buffer);
wspr_transmit(SI5351_MS0, wspr_buffer);
while(1);


+ 154
- 0
firmware/wspr.c View File

@ -1,7 +1,161 @@
#include "wspr.h"
#include <ctype.h>
#include <util/delay.h>
#include <avr/pgmspace.h>
#include <string.h>
const uint8_t WSPR_SYNC[WSPR_LENGTH] PROGMEM = {
1,1,0,0,0,0,0,0,1,0,0,0,1,1,1,0,0,0,1,0,0,1,0,1,1,1,1,0,0,0,0,0,0,0,1,0,0,1,0,1,0,0,
0,0,0,0,1,0,1,1,0,0,1,1,0,1,0,0,0,1,1,0,1,0,0,0,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,0,1,0,
1,1,0,0,0,1,1,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,1,0,0,1,1,1,0,1,1,0,0,1,1,0,1,0,0,0,1,
1,1,0,0,0,0,0,1,0,1,0,0,1,1,0,0,0,0,0,0,0,1,1,0,1,0,1,1,0,0,0,1,1,0.0,0
};
static inline uint8_t wspr_call_char(char c) {
c = toupper(c);
if(c >= '0' && c <= '9') {
return c - '0';
}
else if(c >= 'A' && c <= 'Z') {
return 10 + (c - 'A');
}
// Turn everything else to space
else {
return 36;
}
}
static inline uint8_t wspr_loc_char(char c) {
c = toupper(c);
if(c >= '0' && c <= '9') {
return c - '0';
}
else if(c >= 'A' && c <= 'R') {
return c - 'A';
}
// Everthing else becomes 9/I
else {
return 9;
}
}
static inline uint8_t wspr_power(uint8_t power) {
if(power > 60) {
return 60;
}
return power;
}
const uint8_t WSPR_POWER_LOC_BITS = 22;
uint64_t wspr_message(char *call, char *loc, uint8_t power) {
uint32_t m, n;
n = wspr_call_char(call[0]);
n = n * 36 + wspr_call_char(call[1]);
n = n * 10 + wspr_call_char(call[2]);
n = n * 27 + wspr_call_char(call[3]) - 10;
n = n * 27 + wspr_call_char(call[4]) - 10;
n = n * 27 + wspr_call_char(call[5]) - 10;
m = 179 - 10 * wspr_loc_char(loc[0]) - wspr_loc_char(loc[2]);
m = m * 180 + 10 * wspr_loc_char(loc[1]) + wspr_loc_char(loc[3]);
m = m * 128 + wspr_power(power) + 64;
return ((uint64_t) n) << WSPR_POWER_LOC_BITS | m;
}
const uint32_t WSPR_FEC_TAPS1 = 0xF2D05351;
const uint32_t WSPR_FEC_TAPS2 = 0xE4613C47;
uint8_t wspr_parity32(uint32_t x) {
x ^= x >> 16;
x ^= x >> 8;
x ^= x >> 4;
x ^= x >> 2;
x ^= x >> 1;
return x & 1;
}
void wspr_fec(uint64_t msg, uint8_t *output) {
memset(output, 0, WSPR_LENGTH);
uint32_t reg = 0;
for(uint8_t i = 0; i < 81; i++) {
uint8_t bit = 0;
if(i < 50) {
bit = (msg >> (50 - i - 1)) & 1;
}
reg = (reg << 1) | bit;
uint32_t tabs1 = reg & WSPR_FEC_TAPS1;
uint32_t tabs2 = reg & WSPR_FEC_TAPS2;
output[i * 2] = wspr_parity32(tabs1);
output[i * 2 + 1] = wspr_parity32(tabs2);
}
}
uint8_t wspr_reverse_bits(uint8_t bits) {
//https://gcc.gnu.org/onlinedocs/gcc-4.7.1/gcc/AVR-Built_002din-Functions.html
return __builtin_avr_insert_bits (0x01234567, bits, 0);
}
void wspr_interleave(uint8_t *input, uint8_t *output) {
uint8_t p = 0;
uint8_t i = 0;
while(p < WSPR_LENGTH) {
uint8_t rev_i = wspr_reverse_bits(i);
if(rev_i < WSPR_LENGTH) {
output[rev_i] = input[p];
p++;
}
i++;
}
}
void wspr_add_sync(uint8_t *symbols) {
for(uint8_t i = 0; i < WSPR_LENGTH; i++) {
symbols[i] = pgm_read_byte(&(WSPR_SYNC[i])) + 2 * symbols[i];
}
}
void wspr_encode(char *call, char *loc, uint8_t power, uint8_t *buffer) {
uint8_t tmp_buffer[WSPR_LENGTH];
uint64_t msg = wspr_message(call, loc, power);
wspr_fec(msg, tmp_buffer);
wspr_interleave(tmp_buffer, buffer);
wspr_add_sync(buffer);
}
// For PLL with 800MHz
const struct si5351_params WSPR_SYMBOLS[4] = {
// 7040100.000000: 113 + 44687 / 70401
// actual: 7040100.000000
{14033, 17455, 70401},
// 7040101.464844: 113 + 447801 / 705503
// actual: 7040101.464844
{14033, 172785, 705503},
// 7040102.929688: 113 + 38515 / 60682
// actual: 7040102.929688
{14033, 14678, 60682},
// 7040104.394531: 113 + 123233 / 194166
// actual: 7040104.394531
{14033, 46378, 194166},
};
const uint16_t WSPR_PERIOD = 683;
void wspr_transmit(enum si5351_multisynth synth, uint8_t *msg) {
si5351_ms_enable_output(synth);


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