/**
* The data returned is coming in at 228000 from the fm / rds library. If we return 1000 samples per call
* then we need to be called 228 times a second.
* Here is what we need to do each pass
* 1. Use the PiRds library to take in the file and prep for FM modulation (Add RDS & pilot tone & separate the stereo etc)
* 2. FM Modulate using the GNURadio implementation of FM modulation.
* 3. Upsample to a higher sample rate so we can have higher bandwidth using the method from http://www.dspguru.com/dsp/faqs/multirate/interpolation
* 4. Frequency shift up to he appropriate location based on our current tuned frequency and the location of our station.
*/
int Transmitter::doWork() {
TRACE("Entered Method");
// Only do work if our frequency is within the bandwidth of the tuner.
TRACE("Checking if there is any reason to do work.");
if (abs(centerFrequency - tunedFrequency) > 0.5 * MAX_OUTPUT_SAMPLE_RATE) {
TRACE("Transmitter is not in tuned range. Returning all zeros.");
basebandCmplxUpSampledTuned.resize(numSamples*10, std::complex<float>(0.0,0.0));
return 0;
} else {
TRACE("Receiving samples from fm_mpx_get_samples() for file: ");
if( fm_mpx_get_samples(&mpx_buffer[0], &rds_content, &rds_sig_info, &fm_mpx_status_struct) < 0 ) {
ERROR("Error occurred adding RDS data to sound file.");
return -1;
}
TRACE("Scaling samples");
mpx_buffer /= 10.;
TRACE("FM Modulating the real data");
fm.modulate(mpx_buffer, basebandCmplx);
TRACE("Polyphase filtering for upsampling");
for (int i = 0; i < 10; ++i) {
polyphaseFilters[i]->run();
for (int ii = 0; ii < basebandCmplx_polyPhaseout.size(); ++ii) {
basebandCmplxUpSampled[i + 10*ii] = basebandCmplx_polyPhaseout[ii];
}
}
{
boost::mutex::scoped_lock lock(tunerMutex);
TRACE("Tuning to the relative frequency");
tuner.run();
}
TRACE("Exited Method");
return 0;
}
}
/* Simple test program */
int main(int argc, char **argv) {
if(argc < 4) {
fprintf(stderr, "Error: missing argument.\n");
fprintf(stderr, "Syntax: rds_wav <in_audio.wav> <out_mpx.wav> <text>\n");
return EXIT_FAILURE;
}
// YLB Stuff is here
struct rds_struct rds_status_struct;
struct fm_mpx_struct fm_mpx_status_struct;
fm_mpx_status_struct.phase_38 = 0;
fm_mpx_status_struct.phase_19 = 0;
fm_mpx_status_struct.audio_index = 0;
fm_mpx_status_struct.audio_len = 0;
fm_mpx_status_struct.fir_index = 0;
unsigned int i;
for (i = 0; i < FIR_SIZE; i++) {
fm_mpx_status_struct.fir_buffer_mono[i] = 0;
fm_mpx_status_struct.fir_buffer_stereo[i] = 0;
}
rds_status_struct.pi = 0x1234;
set_rds_ps(argv[3], &rds_status_struct);
set_rds_rt(argv[3], &rds_status_struct);
// Done with YLB stuff
//set_rds_ps(argv[3]);
//set_rds_rt(argv[3]);
char *in_file = argv[1];
if(strcmp("NONE", argv[1]) == 0) in_file = NULL;
// if(fm_mpx_open(in_file, LENGTH) != 0) {
if(fm_mpx_open(in_file, LENGTH, &fm_mpx_status_struct) != 0) {
printf("Could not setup FM mulitplex generator.\n");
return EXIT_FAILURE;
}
// Set the format of the output file
SNDFILE *outf;
SF_INFO sfinfo;
sfinfo.frames = LENGTH;
sfinfo.samplerate = 228000;
sfinfo.channels = 1;
sfinfo.format = SF_FORMAT_WAV | SF_FORMAT_PCM_16;
sfinfo.sections = 1;
sfinfo.seekable = 0;
// Open the output file
char *out_file = argv[2];
if (! (outf = sf_open(out_file, SFM_WRITE, &sfinfo))) {
fprintf(stderr, "Error: could not open output file %s.\n", out_file);
return EXIT_FAILURE;
}
float mpx_buffer[LENGTH];
for(int j=0; j<40; j++) {
if( fm_mpx_get_samples(mpx_buffer, &rds_status_struct, &fm_mpx_status_struct) < 0 ) break;
// scale samples
for(int i=0; i<LENGTH; i++) {
mpx_buffer[i] /= 10.;
// printf("%f, ", mpx_buffer[i]);
}
exit(0);
if(sf_write_float(outf, mpx_buffer, LENGTH) != LENGTH) {
fprintf(stderr, "Error: writing to file %s.\n", argv[1]);
return EXIT_FAILURE;
}
}
if(sf_close(outf) ) {
fprintf(stderr, "Error: closing file %s.\n", argv[1]);
}
fm_mpx_close(&fm_mpx_status_struct);
return EXIT_SUCCESS;
}
int tx(uint32_t carrier_freq, char *audio_file, uint16_t pi, char *ps, char *rt, float ppm, char *control_pipe) {
// Catch all signals possible - it is vital we kill the DMA engine
// on process exit!
for (int i = 0; i < 64; i++) {
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = terminate;
sigaction(i, &sa, NULL);
}
dma_reg = map_peripheral(DMA_VIRT_BASE, DMA_LEN);
pwm_reg = map_peripheral(PWM_VIRT_BASE, PWM_LEN);
clk_reg = map_peripheral(CLK_VIRT_BASE, CLK_LEN);
gpio_reg = map_peripheral(GPIO_VIRT_BASE, GPIO_LEN);
// Use the mailbox interface to the VC to ask for physical memory.
mbox.handle = mbox_open();
if (mbox.handle < 0)
fatal("Failed to open mailbox. Check kernel support for vcio / BCM2708 mailbox.\n");
printf("Allocating physical memory: size = %d ", NUM_PAGES * 4096);
if(! (mbox.mem_ref = mem_alloc(mbox.handle, NUM_PAGES * 4096, 4096, MEM_FLAG))) {
fatal("Could not allocate memory.\n");
}
// TODO: How do we know that succeeded?
printf("mem_ref = %u ", mbox.mem_ref);
if(! (mbox.bus_addr = mem_lock(mbox.handle, mbox.mem_ref))) {
fatal("Could not lock memory.\n");
}
printf("bus_addr = %x ", mbox.bus_addr);
if(! (mbox.virt_addr = mapmem(BUS_TO_PHYS(mbox.bus_addr), NUM_PAGES * 4096))) {
fatal("Could not map memory.\n");
}
printf("virt_addr = %p\n", mbox.virt_addr);
// GPIO4 needs to be ALT FUNC 0 to output the clock
gpio_reg[GPFSEL0] = (gpio_reg[GPFSEL0] & ~(7 << 12)) | (4 << 12);
// Program GPCLK to use MASH setting 1, so fractional dividers work
clk_reg[GPCLK_CNTL] = 0x5A << 24 | 6;
udelay(100);
clk_reg[GPCLK_CNTL] = 0x5A << 24 | 1 << 9 | 1 << 4 | 6;
ctl = (struct control_data_s *) mbox.virt_addr;
dma_cb_t *cbp = ctl->cb;
uint32_t phys_sample_dst = CM_GP0DIV;
uint32_t phys_pwm_fifo_addr = PWM_PHYS_BASE + 0x18;
// Calculate the frequency control word
// The fractional part is stored in the lower 12 bits
uint32_t freq_ctl = ((float)(PLLFREQ / carrier_freq)) * ( 1 << 12 );
for (int i = 0; i < NUM_SAMPLES; i++) {
ctl->sample[i] = 0x5a << 24 | freq_ctl; // Silence
// Write a frequency sample
cbp->info = BCM2708_DMA_NO_WIDE_BURSTS | BCM2708_DMA_WAIT_RESP;
cbp->src = mem_virt_to_phys(ctl->sample + i);
cbp->dst = phys_sample_dst;
cbp->length = 4;
cbp->stride = 0;
cbp->next = mem_virt_to_phys(cbp + 1);
cbp++;
// Delay
cbp->info = BCM2708_DMA_NO_WIDE_BURSTS | BCM2708_DMA_WAIT_RESP | BCM2708_DMA_D_DREQ | BCM2708_DMA_PER_MAP(5);
cbp->src = mem_virt_to_phys(mbox.virt_addr);
cbp->dst = phys_pwm_fifo_addr;
cbp->length = 4;
cbp->stride = 0;
cbp->next = mem_virt_to_phys(cbp + 1);
cbp++;
}
cbp--;
cbp->next = mem_virt_to_phys(mbox.virt_addr);
// Here we define the rate at which we want to update the GPCLK control
// register.
//
// Set the range to 2 bits. PLLD is at 500 MHz, therefore to get 228 kHz
// we need a divisor of 500000 / 2 / 228 = 1096.491228
//
// This is 1096 + 2012*2^-12 theoretically
//
// However the fractional part may have to be adjusted to take the actual
// frequency of your Pi's oscillator into account. For example on my Pi,
// the fractional part should be 1916 instead of 2012 to get exactly
// 228 kHz. However RDS decoding is still okay even at 2012.
//
// So we use the 'ppm' parameter to compensate for the oscillator error
float divider = (500000./(2*228*(1.+ppm/1.e6)));
uint32_t idivider = (uint32_t) divider;
uint32_t fdivider = (uint32_t) ((divider - idivider)*pow(2, 12));
printf("ppm corr is %.4f, divider is %.4f (%d + %d*2^-12) [nominal 1096.4912].\n",
ppm, divider, idivider, fdivider);
pwm_reg[PWM_CTL] = 0;
udelay(10);
clk_reg[PWMCLK_CNTL] = 0x5A000006; // Source=PLLD and disable
udelay(100);
// theorically : 1096 + 2012*2^-12
clk_reg[PWMCLK_DIV] = 0x5A000000 | (idivider<<12) | fdivider;
udelay(100);
clk_reg[PWMCLK_CNTL] = 0x5A000216; // Source=PLLD and enable + MASH filter 1
udelay(100);
pwm_reg[PWM_RNG1] = 2;
udelay(10);
pwm_reg[PWM_DMAC] = PWMDMAC_ENAB | PWMDMAC_THRSHLD;
udelay(10);
pwm_reg[PWM_CTL] = PWMCTL_CLRF;
udelay(10);
pwm_reg[PWM_CTL] = PWMCTL_USEF1 | PWMCTL_PWEN1;
udelay(10);
// Initialise the DMA
dma_reg[DMA_CS] = BCM2708_DMA_RESET;
udelay(10);
dma_reg[DMA_CS] = BCM2708_DMA_INT | BCM2708_DMA_END;
dma_reg[DMA_CONBLK_AD] = mem_virt_to_phys(ctl->cb);
dma_reg[DMA_DEBUG] = 7; // clear debug error flags
dma_reg[DMA_CS] = 0x10880001; // go, mid priority, wait for outstanding writes
uint32_t last_cb = (uint32_t)ctl->cb;
// Data structures for baseband data
float data[DATA_SIZE];
int data_len = 0;
int data_index = 0;
// Initialize the baseband generator
if(fm_mpx_open(audio_file, DATA_SIZE) < 0) return 1;
// Initialize the RDS modulator
char myps[9] = {0};
set_rds_pi(pi);
set_rds_rt(rt);
uint16_t count = 0;
uint16_t count2 = 0;
int varying_ps = 0;
if(ps) {
set_rds_ps(ps);
printf("PI: %04X, PS: \"%s\".\n", pi, ps);
} else {
printf("PI: %04X, PS: <Varying>.\n", pi);
varying_ps = 1;
}
printf("RT: \"%s\"\n", rt);
// Initialize the control pipe reader
if(control_pipe) {
if(open_control_pipe(control_pipe) == 0) {
printf("Reading control commands on %s.\n", control_pipe);
} else {
printf("Failed to open control pipe: %s.\n", control_pipe);
control_pipe = NULL;
}
}
printf("Starting to transmit on %3.1f MHz.\n", carrier_freq/1e6);
for (;;) {
// Default (varying) PS
if(varying_ps) {
if(count == 512) {
snprintf(myps, 9, "%08d", count2);
set_rds_ps(myps);
count2++;
}
if(count == 1024) {
set_rds_ps("RPi-Live");
count = 0;
}
count++;
}
if(control_pipe && poll_control_pipe() == CONTROL_PIPE_PS_SET) {
varying_ps = 0;
}
usleep(5000);
uint32_t cur_cb = mem_phys_to_virt(dma_reg[DMA_CONBLK_AD]);
int last_sample = (last_cb - (uint32_t)mbox.virt_addr) / (sizeof(dma_cb_t) * 2);
int this_sample = (cur_cb - (uint32_t)mbox.virt_addr) / (sizeof(dma_cb_t) * 2);
int free_slots = this_sample - last_sample;
if (free_slots < 0)
free_slots += NUM_SAMPLES;
while (free_slots >= SUBSIZE) {
// get more baseband samples if necessary
if(data_len == 0) {
if( fm_mpx_get_samples(data) < 0 ) {
terminate(0);
}
data_len = DATA_SIZE;
data_index = 0;
}
float dval = data[data_index] * (DEVIATION / 10.);
data_index++;
data_len--;
int intval = (int)((floor)(dval));
//int frac = (int)((dval - (float)intval) * SUBSIZE);
ctl->sample[last_sample++] = (0x5A << 24 | freq_ctl) + intval; //(frac > j ? intval + 1 : intval);
if (last_sample == NUM_SAMPLES)
last_sample = 0;
free_slots -= SUBSIZE;
}
last_cb = (uint32_t)mbox.virt_addr + last_sample * sizeof(dma_cb_t) * 2;
}
return 0;
}