+/**
+ * Does the sample acquisition. If threshold is specified, the actual sampling
+ * is not commenced until the threshold has been reached.
+ * This method implements decimation and quantization in order to
+ * be able to provide longer sample traces.
+ * Uses the following global settings:
+ * - decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
+ * - bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
+ * - averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
+ * value that will be used is the average value of the three samples.
+ *
+ * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
+ * to -1 to ignore threshold.
+ * @param silent - is true, now outputs are made. If false, dbprints the status
+ * @return the number of bits occupied by the samples.
+ */
+uint32_t DoAcquisition125k_internal(int trigger_threshold,bool silent)
+{
+ //.
+ uint8_t *dest = (uint8_t *)BigBuf;
+ int bufsize = BIGBUF_SIZE;
+ memset(dest, 0, bufsize);
+
+ if(bits_per_sample < 1) bits_per_sample = 1;
+ if(bits_per_sample > 8) bits_per_sample = 8;
+
+ if(decimation < 1) decimation = 1;
+
+ // Use a bit stream to handle the output
+ BitstreamOut data = { dest , 0, 0};
+ int sample_counter = 0;
+ uint8_t sample = 0;
+ //If we want to do averaging
+ uint32_t sample_sum =0 ;
+ uint32_t sample_total_numbers =0 ;
+ uint32_t sample_total_saved =0 ;
+
+ while(!BUTTON_PRESS()) {
+ WDT_HIT();
+ if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+ AT91C_BASE_SSC->SSC_THR = 0x43;
+ LED_D_ON();
+ }
+ if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+ sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+ LED_D_OFF();
+ if (trigger_threshold != -1 && sample < trigger_threshold)
+ continue;
+
+ trigger_threshold = -1;
+ sample_total_numbers++;
+
+ if(averaging)
+ {
+ sample_sum += sample;
+ }
+ //Check decimation
+ if(decimation > 1)
+ {
+ sample_counter++;
+ if(sample_counter < decimation) continue;
+ sample_counter = 0;
+ }
+ //Averaging
+ if(averaging && decimation > 1) {
+ sample = sample_sum / decimation;
+ sample_sum =0;
+ }
+ //Store the sample
+ sample_total_saved ++;
+ if(bits_per_sample == 8){
+ dest[sample_total_saved-1] = sample;
+ data.numbits = sample_total_saved << 3;//Get the return value correct
+ if(sample_total_saved >= bufsize) break;
+ }
+ else{
+ pushBit(&data, sample & 0x80);
+ if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
+ if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
+ if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
+ if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
+ if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
+ if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
+ //Not needed, 8bps is covered above
+ //if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
+ if((data.numbits >> 3) +1 >= bufsize) break;
+ }
+ }
+ }
+
+ if(!silent)
+ {
+ Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
+ Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
+ dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
+ }
+ return data.numbits;