     trace.flush();
   }
   INFO("per sample:%ul us", trace.measure / SAMPLES);
-  Ksps = ((float) SAMPLES * 1000.0) / trace.measure;
+  ksps = ((float) SAMPLES * 1000.0) / trace.measure;
   trace << PSTR("effective sample rate (") << SAMPLES << PSTR(" samples):")
-	<< Ksps << PSTR(" Ksps")
+	<< ksps << PSTR(" ksps")
 	<< endl;
   trace << PSTR("idle:") << (idle * 100.0) / RTC::micros() << '%'
 	<< endl;
   sleep(5);
 
-  // 1000 samples with 125 us period; pipe-line sample request and print
+  // 1000 samples with 250 us period; pipe-line sample request and print
   idle = 0L;
   MEASURE("performance:", 1) {
     for (uint16_t i = 0; i < SAMPLES;) {
       probe.sample_request();
-      PERIODIC(timer, 500) {
+      PERIODIC(timer, 250) {
 	uint16_t sample = probe.sample_await();
 	probe.sample_request();
 	trace << sample << endl;

void setup()
{
  // Start serial output with given baud-rate
  uart.begin(500000);
  // uart.begin(2000000);
  // uart.begin(1000000);
  // uart.begin(500000);

  // Install capture idle time
  ::yield = iowait;

  // Power up ADC
  AnalogPin::powerup();

  // Start timers
  Watchdog::begin();
  RTC::begin();
