InfiniTime/doc/PinetimeStubWithNrf52DK.md

Build a stub for PineTime using NRF52-DK

NRF52-DK is the official developpment kit for the NRF52832 SoC from Nordic Semiconductor used in the PineTime.

This development kit can be very useful for PineTime development:

• You can use its embedded JLink SWD programmer/debugger to program and debug your code on the PineTime
• As it's based on the same SoC than the PineTime, you can program it to actually run the same code as the PineTime.

This page is about the 2nd point : we will build a stub that will allow us to run the same code you can run on the PineTime. This will allow you to work more easily if you don't have a PineTime dev kit around, if you don't want to modify your dev kit for SWD programming, or if you want to use some feature from the NRF52-DK (like power measurement).

This stub only implements the display, the button and the BLE radio. The other features from the pintime are missing:

• heart rate sensor
• SPI flash
• touchpad
• accelerometer

These devices could be added on this stub, but I do not have the parts to try them out for now.

Here are the parts you need to build this simulator:

• NRF52-DK
• An ST7889 display (I bought this one)
• A push-button (the one I use comes from a previous project build around ESP8266 board Wemos D1 Mini).
• Dupont wires

You just need to make the following connections:

NRF52-DK	ST7889 display
VDD	VCC
GND	GND
P0.03	SDA
P0.26	RES
P0.02	SCL
P0.18	DC

NRF52-DK	Push Button
P0.13	Button IN (D3 in my case)
GND	GND

You also need to enable the I/O expander to disconnect pins from the buttons and LED on the NRF52-DK and leave them available on the pin headers:

NRF52 -DK	NRF52- DK
DETECT	GND

Now, you should be able to program the SoC on the NRF52-DK board, and use it as if it was running on the PineTime.