Skip to content

Commit

Permalink
Add prediv option, fix tuning on RPi4
Browse files Browse the repository at this point in the history
  • Loading branch information
@miegl
miegl committed Apr 16, 2022
1 parent 9f4cbc3 commit 66af3bd
Show file tree
Hide file tree
Showing 2 changed files with 68 additions and 57 deletions.
2 changes: 1 addition & 1 deletion src/fm_mpx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -91,7 +91,7 @@ int fm_mpx_open(char *filename, size_t buf_len, int cutoff_freq, int preemphasis

soxr_error_t soxr_error;
soxr_quality_spec_t q_spec = soxr_quality_spec(SOXR_LQ, 0);
double passband_end = (double)cutoff_freq/in_samplerate;
//double passband_end = (double)cutoff_freq/in_samplerate;
//q_spec.passband_end = passband_end > 0.5 ? passband_end : 0.5;
soxr_io_spec_t io_spec = soxr_io_spec((soxr_datatype_t)SOXR_FLOAT32_I, (soxr_datatype_t)SOXR_FLOAT64_I);
soxr_runtime_spec_t runtime_spec = soxr_runtime_spec(!1);
Expand Down
123 changes: 67 additions & 56 deletions src/pi_fm_adv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -372,7 +372,7 @@ static volatile void *map_peripheral(uint32_t base, uint32_t len)



int tx(uint32_t carrier_freq, int divider, char *audio_file, int rds, uint16_t pi, char *ps, char *rt, int *af_array, float ppm, float deviation, float mpx, int cutoff, int preemphasis_cutoff, char *control_pipe, int pty, int tp, int power, int pll, int gpclk, int *gpio, int wait, int srate, int nochan) {
int tx(uint32_t carrier_freq, int divider, int prediv, char *audio_file, int rds, uint16_t pi, char *ps, char *rt, int *af_array, float ppm, float deviation, float mpx, int cutoff, int preemphasis_cutoff, char *control_pipe, int pty, int tp, int power, int pll, int gpclk, int *gpio, int wait, int srate, int nochan) {
// Catch only important signals
for (int i = 0; i < 25; i++) {
struct sigaction sa;
Expand Down Expand Up @@ -431,17 +431,12 @@ int tx(uint32_t carrier_freq, int divider, char *audio_file, int rds, uint16_t p
else if(pll == 5) clk_reg[CM_PLLC] = (0x5a<<24) | 0x22a; // Enable PLLC_PER
udelay(100);

int per_div = 1;
#if (RASPI) == 4
per_div = 2;
#endif

if(pll == 4) {
clk_reg[PLLA_CORE] = (0x5a<<24) | (1<<8); // Disable
clk_reg[PLLA_PER] = (0x5a<<24) | per_div;
clk_reg[PLLA_PER] = (0x5a<<24) | prediv;
} else if(pll == 5) {
clk_reg[PLLC_CORE0] = (0x5a<<24) | (1<<8); // Disable
clk_reg[PLLC_PER] = (0x5a<<24) | per_div;
clk_reg[PLLC_PER] = (0x5a<<24) | prediv;
}
udelay(100);

Expand All @@ -466,7 +461,7 @@ int tx(uint32_t carrier_freq, int divider, char *audio_file, int rds, uint16_t p
}

// Adjust PLLC frequency
freq_ctl = (unsigned int)(((carrier_freq*divider)/(CLOCK_BASE*(1.+ppm/1.e6))*((double)(1<<20))));
freq_ctl = (unsigned int)(((carrier_freq*divider*prediv)/(CLOCK_BASE*(1.+ppm/1.e6))*((double)(1<<20))));
if(pll == 4) clk_reg[PLLA_CTRL] = (0x5a<<24) | (0x21<<12) | (freq_ctl>>20); // Integer part
else if(pll == 5) clk_reg[PLLC_CTRL] = (0x5a<<24) | (0x21<<12) | (freq_ctl>>20); // Integer part
freq_ctl&=0xFFFFF;
Expand Down Expand Up @@ -618,7 +613,7 @@ int tx(uint32_t carrier_freq, int divider, char *audio_file, int rds, uint16_t p

printf("Starting to transmit on %3.1f MHz.\n", carrier_freq/1e6);

double deviation_scale_factor = (divider*(deviation)/((CLOCK_BASE*(1.+ppm/1.e6))/((double)(1<<20))));
double deviation_scale_factor = (divider*prediv*(deviation)/((CLOCK_BASE*(1.+ppm/1.e6))/((double)(1<<20))));

for (;;) {

Expand All @@ -644,12 +639,10 @@ int tx(uint32_t carrier_freq, int divider, char *audio_file, int rds, uint16_t p
}

double dval = data[data_index]*deviation_scale_factor/10;
//if(dval > deviation_scale_factor) printf("Alert: dval = %f\n", dval);
if(dval > deviation_scale_factor) {
samples_over_deviation++;
//dval = deviation_scale_factor;
}
//int intval = ((int)(dval)); //((int)((dval)) & ~0x3);
data_index++;
data_len--;

Expand All @@ -669,6 +662,53 @@ int tx(uint32_t carrier_freq, int divider, char *audio_file, int rds, uint16_t p
return 0;
}

int findDivider(uint32_t carrier_freq, float deviation, double xtal_freq_recip) {
int divider, best_divider = 0;
int min_int_multiplier, max_int_multiplier;
int int_multiplier;
double frac_multiplier;
int fom, best_fom = 0;
int solution_count = 0;
for(divider = 2; divider < 50; divider += 1)
{
if(carrier_freq * divider > 1400e6) break;

max_int_multiplier=((int)((double)(carrier_freq + 10 + (deviation)) * divider * xtal_freq_recip));
min_int_multiplier=((int)((double)(carrier_freq - 10 - (deviation)) * divider * xtal_freq_recip));
if(min_int_multiplier != max_int_multiplier) continue;

solution_count++;
fom = 0;

if(carrier_freq * divider > 1000e6) fom++; // Prefer frequencies close to 1.1 Ghz
if(carrier_freq * divider < 1200e6) fom++;

if(carrier_freq * divider > 900e6) fom++;
if(carrier_freq * divider < 1300e6) fom++;

if(carrier_freq * divider > 800e6) fom++;
if(carrier_freq * divider < 1400e6) fom++;

frac_multiplier = ((double)(carrier_freq) * divider * xtal_freq_recip);
int_multiplier = (int)frac_multiplier;
frac_multiplier = frac_multiplier - int_multiplier;
if((frac_multiplier > 0.3) && (frac_multiplier < 0.7)) fom++; // Prefer mulipliers away from integer boundaries
if((frac_multiplier > 0.2) && (frac_multiplier < 0.8)) fom++;

if(fom > best_fom) // Best match so far
{
best_fom = fom;
best_divider = divider;
}
}

if(!solution_count & !best_divider) {
fatal("No tuning solution found. You can specify the divider manually by setting the -div parameter.\n");
}

return best_divider;
}

int main(int argc, char **argv) {
int opt;

Expand All @@ -688,6 +728,12 @@ int main(int argc, char **argv) {
int pty = 15;
int tp = 1;
int divc = 0;
int prediv = 1;

#if (RASPI) == 4
prediv = 2;
#endif

int power = 7;
int gpclk = 0;
int gpio[5] = {0};
Expand All @@ -707,6 +753,7 @@ int main(int argc, char **argv) {
{"cutoff", required_argument, NULL, 'c'},
{"preemph", required_argument, NULL, 'P'},
{"div", required_argument, NULL, 'D'},
{"prediv", required_argument, NULL, 'r'},
{"mpx", required_argument, NULL, 'm'},
{"power", required_argument, NULL, 'w'},
{"gpclk", required_argument, NULL, 'G'},
Expand Down Expand Up @@ -774,6 +821,10 @@ int main(int argc, char **argv) {
divc = atoi(optarg);
break;

case 'r': //prediv
prediv = atoi(optarg);
break;

case 'm': //mpx
mpx = atof(optarg);
break;
Expand Down Expand Up @@ -849,7 +900,7 @@ int main(int argc, char **argv) {
fatal("Help:\n"
"Syntax: pi_fm_adv [--audio (-a) file] [--freq (-f) frequency] [--dev (-d) deviation] [--ppm (-p) ppm-error]\n"
" [--cutoff (-c) cutoff-freq] [--preemph (-P) preemphasis] [--div (-D) divider] \n"
" [--mpx (-m) mpx-power] [--power (-w) output-power] [--gpio (-g) gpio-pin]\n"
" [--prediv (-r) prediv] [--mpx (-m) mpx-power] [--power (-w) output-power] [--gpio (-g) gpio-pin]\n"
" [--gpclk (-G) gpclk {0, 1, 2}] [--pll (-l) PLL {a, c}] [--wait (-W) wait-switch]\n"
" [--rds rds-switch] [--pi pi-code] [--ps ps-text] [--rt radiotext] [--tp traffic-program]\n"
" [--pty program-type] [--af alternative-freq] [--ctl (-C) control-pipe]\n");
Expand All @@ -872,51 +923,11 @@ int main(int argc, char **argv) {
alternative_freq[0] = af_size;

double xtal_freq_recip=1.0/CLOCK_BASE;
int divider, best_divider = 0;
int min_int_multiplier, max_int_multiplier;
int int_multiplier;
double frac_multiplier;
int fom, best_fom = 0;
int solution_count = 0;
for(divider = 2; divider < 50; divider += 1)
{
if(carrier_freq * divider > 1400e6) break;

max_int_multiplier=((int)((double)(carrier_freq + 10 + (deviation)) * divider * xtal_freq_recip));
min_int_multiplier=((int)((double)(carrier_freq - 10 - (deviation)) * divider * xtal_freq_recip));
if(min_int_multiplier != max_int_multiplier) continue;

solution_count++;
fom = 0;

if(carrier_freq * divider > 900e6) fom++; // Prefer frequencies close to 1.0 Ghz
if(carrier_freq * divider < 1100e6) fom++;

if(carrier_freq * divider > 800e6) fom++;
if(carrier_freq * divider < 1200e6) fom++;

frac_multiplier = ((double)(carrier_freq) * divider * xtal_freq_recip);
int_multiplier = (int)frac_multiplier;
frac_multiplier = frac_multiplier - int_multiplier;
if((frac_multiplier > 0.2) && (frac_multiplier < 0.8)) fom++; // Prefer mulipliers away from integer boundaries

if(fom > best_fom) // Best match so far
{
best_fom = fom;
best_divider = divider;
}
}

if(divc) {
best_divider = divc;
}
else if(!solution_count & !best_divider) {
fatal("No tuning solution found. You can specify the divider manually by setting the -div parameter.\n");
}
if(divc == 0) divc = findDivider(carrier_freq*prediv, deviation, xtal_freq_recip);

printf("Carrier: %3.2f Mhz, VCO: %4.1f MHz, Multiplier: %f, Divider: %d\n", carrier_freq/1e6, (double)carrier_freq * best_divider / 1e6, carrier_freq * best_divider * xtal_freq_recip, best_divider);
printf("Carrier: %3.2f Mhz, VCO: %4.1f MHz, Multiplier: %f, Divider: %d\n", carrier_freq/1e6, (double)carrier_freq*prediv * divc / 1e6, carrier_freq*prediv * divc * xtal_freq_recip, divc);

int errcode = tx(carrier_freq, best_divider, audio_file, rds, pi, ps, rt, alternative_freq, ppm, deviation, mpx, cutoff, preemphasis_cutoff, control_pipe, pty, tp, power, pll, gpclk, gpio, wait, srate, nochan);
int errcode = tx(carrier_freq, divc, prediv, audio_file, rds, pi, ps, rt, alternative_freq, ppm, deviation, mpx, cutoff, preemphasis_cutoff, control_pipe, pty, tp, power, pll, gpclk, gpio, wait, srate, nochan);

terminate(errcode);
}

0 comments on commit 66af3bd

Please sign in to comment.