1.d. Jumper settings
As shown in the picture below, the Wixel Shield has a number of surface-mount jumpers that can be used to customize some of the on-board connections.
Configuration jumpers on the Wixel Shield for Arduino, v1.1.
- Reset circuit jumper: This jumper allows a logic high on the Wixel’s P0_0 pin to reset the Arduino by driving its RESET pin low. It is by default.
- Arduino RX=0 jumper: The Wixel’s TX output (P1_6) goes to a level shifter that converts it to the Arduino’s IOREF voltage. The output of this level shifter is connected to the Arduino’s pin 0 (RX) by this jumper. It is by default, but if you want to use a different pin as RX on your Arduino (e.g. if you are using software serial), you can cut this jumper and make your own connection from the through-hole labeled “ArdRX” to the desired pin.
- Arduino TX=1 jumper: This jumper connects the Arduino’s pin 1 (TX) to the input of a level shifter that converts it to 3.3 V for the Wixel’s RX input (P1_7). It is by default, but if you want to use a different pin as TX on your Arduino, you can cut this jumper and remap the connection with the through-hole labeled “ArdTX”.
- Wixel RX jumper: If you are not using serial communication and the output of the level shifter interferes with the Wixel’s P1_7 pin in your application, you can cut this jumper ( by default) to disconnect the level shifter from P1_7. This jumper is only available on the Wixel Shield v1.1, not the original (v1.0).
- IOREF=5V jumper: By default, the level shifters on the Wixel Shield v1.1 convert between the Arduino’s IOREF voltage and the Wixel’s 3.3 V, allowing the shield to work automatically with both 5 V and 3.3 V Arduino boards. The IOREF pin was introduced by the Arduino Uno R3 and is present on all newer Arduinos, but older boards like the Duemilanove do not have this pin. The shield can still be used with such an Arduino board by bridging this jumper (which is by default) to connect 5V to IOREF. This jumper is only available on the Wixel Shield v1.1, not the original (v1.0), which always shifts between 5 V for the Arduino and 3.3 V for the Wixel.