The RFzero BoardTest program can be used for checking your RFzero either after assembly or later on if you suspect that there may also be something wrong with your board.


To test your RFzero using BoardTest requires the following peripheral devices connected

  • A LCD with minimum two line and 16 characters. Only HD44780 LCD parallel interface is supported
  • The USB port connected to the Serial Monitor or a similar terminal program
  • A GPS antenna
  • A frequency counter, oscilloscope or receiver able to detect the 10 MHz signal

The BoardTest welcome message.

The LCD shows the status during testing.

Pin check

BoardTest sets each of the A0-A5, D0-D9, D16-D21 pins active one by one for 250 ms before jumping to the next. This can be verified using the on-board Test LED. The LCD shows which pin is currently active, L:xx.

This verifies the connection to the various pins. Because the LCD is connected this verified those pins (D10-D15).

USB check

If data is received on the USB port the first eight characters are displayed on the LCD, U:xxxxxxxx. The data received is also echoed on the USB.

This verifies the USB connection both ways.

EEPROM check

A random value is written to the EEPROM and read back. The result is shown on the LCD, E:OK/No.

This verifies the I2C/Wire bus and the EEPROM connection.

GPS check

All default NMEA except the $GPGGA frame are are disabled.

GPS data is echoed on the USB port. The PPS_LED will flash when the GPS receiver picks up a valid signal from the satellites.

This verifies the connection to the GPS both ways and the GPS receiver.

Si5351A check

The Si5351A will generate a 10 MHz carrier signal that can be heard in a receiver or shown on a frequency counter.

When the PPS_LED flashes the crystal frequency of the Si5351A is measured and printed on the LCD, F:xxxxxxxx and on the USB too.

This verifies the I2C/Wire bus and the Si5351A connection and the Si5351A RF.

Really simple pin check

If you just want to perform a really simple pin check you can use this example where each pin, A0-D21, is active for 250 ms in a continuous loop.