The nRF52 based chips are the latest version of the popular Bluetooth chip from Nordic that has an ARM Cortex based processor and Bluetooth communications support.
Major differences from the previous nRF51 version includes:
- Based on ARM Cortex M4F instead of ARM M0.
- Support for the latest Bluetooth 5 specification
- On chip NFC support for device bounding and probably something else
The following post centralizes the information that I gathered to start using the demo board that I bought based on the nRF52832 chip.
The eBay,Aliexpress nRF52832 based board:
I’ve bought my nRF52832 based board from AliExpress for around 13€. An higher price than the ESP32 which has both WifI and also blueetooth, but since I really needed to start using the nRF5X base chips I’ve bought what is called “NRF52832 Mini Development Board Gold Core board Wireless Bluetooth Transceiver Module”…
This board build is based on a two boards joined together: one daughter board holding the nRf52832 chip, and another, larger board, exposing the pins, JTAG/SWD connector, power regulator, two leds and two switches. As a bonus the main board was designed for something else and so all the pins silk screen are just plain wrong, but at least the power pins and the SWD pins are correctly identified.
For mapping out correctly the nRF pins to the out pins we need to see the board schematics vs the daughter board pins.
This board schematics are here at this link: NRF52832 Module Test Board V1.0.
And the daughter board pinout is here:
Checking the schematics vs the daughter board pin out we can see that on the pdf schematics file our nRF chip is located where would/should be a CC2640_RGZ module (!…). For example on that module the DIO0 pin corresponds to P25 pin, the DIO1 pin to P26, and so on. We also can check that by, probably sheer luck, the power pins and SWD pins TCLK-SWCLK and TDIO-SWDIO are just right… and so they just reused the main board to hold the nRF52.
Checking out the board and the schematic we can see also that we have a switch on nRF52 pin P04 and two red leds at P30 and P31. The leds can be disconnected by removing the soldering on the nearby solder bridges. The other pins seem free.
As a final note, at least the board that I’ve received, comes with the BLE peripheral Nordic UART example loaded as the running firmware.
More info:Taida Century Gold Core NRF52 board
Programming the board
The board can be programmed at least by two ways:
- Openocd On chip debugger – But a set of patchs are needed to support the nRF52
- Black Magic Probe – Running on a cheap stm32F103C8T6 board – Blue pill
Both ways allow to successfully program the board and debug the running code.
To avoid making this a very long post I’ve split it into further posts how to build the tools necessary to program the nRF52 chip.