The crystal used in atben and atusb has a nominal tolerance of +/- 15 ppm at 22-28 C. Low-cost oscilloscopes typically have a timing accuracy of +/- 100 ppm, which means that only major excursions can be detected by measuring the clock output with such an instrument. Full-speed USB only requires an accuracy of +/- 2500 ppm. We can therefore consider all results within a range of +/- 1000 ppm as sufficient, and perform more precise measurements by other means. This applies to atben as well as to atusb.
atrf-txrx -d net:ben -C 1This configures atben as a promiscuous receiver. The reception of any IEEE 802.15.4 frame or pressing Ctrl-C will terminate the command.
Clock | Action |
---|---|
0 Hz | Check voltages; check that the clock is enabled; check for shorts around crystal; check connectivity of crystal |
0.999-1.001 MHz, ~3.3 Vpp | Perform precision measurement with atrf-xtal |
Other | Check voltages; check for contamination around crystal |
Clock | Action |
---|---|
0 Hz | Check voltages; check for shorts around crystal; check connectivity of crystal |
0.999-1.001 MHz, ~3.3 Vpp | Check presence of firmware; check for shorts on SPI signals; check connectivity of SPI signals |
7.992-8.008 MHz, ~3.3 Vpp | Perform precision measurement with atrf-xtal |
Other | Check voltages; check for contamination around crystal |