By default, the NXP S32K144EVB and microcontroller is using a 5V supply voltage and logic levels which is great for noisy environment or any 5V devices. Many of my displays and sensors use 3.3V logic levels, so I would have to use a level shifter from 5V to 3.3V. There is another way: to change the board for 3.3V logic levels so I can use directly things like a SSD1306 display.
The board schematic overview shows a VDD selection:
In the schematics this is implemented as shown below:
With the R64 (0 Ohm resistor) the board is hard-wired to use 5V (P5V0 to VDD which is the CPU supply voltage). So all what I would need is to remove R64 and install a jumper on J10 to switch between 5V and 3.3V.
Removing R64 is easy with SMD de-solder tweezers tips.
But the through holes for J10 are filled with solder, it seems the board manufacturing data used the wrong solder mask :-(.
After painfully removing the solder from HDR J10, I was able to install a 3-pin header:
With a jumper on 1-2 I have no 3.3V:
Another solution would have been to use a solder bridge between 1-2, but having a jumper is a much nicer way, and I can revert back to 5V VDD if I have to.
Happy Leveling 🙂
PS: that project for the SSD1306 OLED display is available on GitHub.
- S32K144EVB: https://www.nxp.com/products/processors-and-microcontrollers/arm-based-processors-and-mcus/s32-automotive-platform/s32k144-evaluation-board:S32K144EVB