Voltages should be tested in the following order: USB, then I/O, then digital, and finally analog. The table below gives the permissible ranges. Any voltages outside of these ranges indicate a problem.
Domain | Nominal | Minimum | Maximum |
---|---|---|---|
USB | 5.0 V | 4.5 V | 5.25 V |
I/O | 3.3 V | 3.0 V | 3.6 V |
Digital | 1.8 V | 1.7 V | 1.9 V |
Analog | 1.8 V | 1.7 V | 1.9 V |
atrf-txrxor
atrf-txrx -d net:benExit with Ctrl-C.
To produce periodic transmissions in addition to enabling all voltage domains, use
atrf-txrx -p 3 -E 0or
atrf-txrx -d net:ben -p 3 -E 0Again, exit with Ctrl-C. Note that the transmissions may disturb nearby equipment operating in the 2.4 GHz band, such as 802.11 networks. This can be prevented by shorting the antenna to ground.
In case the board does not accept commands, only the USB and I/O voltage can be checked. If they are correct, proceed with checking the clock.
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 |
Note that, if testing a board into which no boot loader has been flashed yet, the clock frequency should be 1 MHz. If an unsuccessful attempt has been made to flash the boot loader, the frequency may be 1 MHz or 8 MHz, depending on how much code was successfully flashed.
atrf-xtal 100The number reported is the number of poll loops the CPU counted. This value should be compared to a reference count obtained with a known to be good atben board on the same Ben at a comparable temperature.
Difference | Action |
---|---|
> +/− 50 ppm | Correct operation |
< −80 ppm | Check soldering of capacitors; check for contamination around crystal |
> +120 ppm | idem |
Other | Divergence can be compensated by adjusting trim value |