7 years, 3 months ago.

what's the frequency of crystal, 16MHz or 8MHz?

i tested a blink example program on my own board, it doesn't work, the frequency of the crystal is 16MHz and my chip version is QFAAG0.

could you give me some advice? Thank you.

best regards, Yuting You.

Question relating to:

The nRF51822-mKIT is a low cost ARM mbed enabled development board for Bluetooth® Smart designs with the nRF51822 SoC. The kit gives access to all GPIO pins via pin headers …

2 Answers

7 years, 3 months ago.

Hi Yuting,

Are you using the new pca10024 mbed board or the old evaluation kit board (PCA10001)? To use the mbed method you need the new PCA10024 board.

When you hook it up to your pc it will look like a "flash drive" . Compile the project here in the cloud and then save it. (to your local drive) Then drop this hex file into the mbed "flash drive". It will program the board and LED 1 will flash.

If you are not using the new PCA10024 board you will need to get one in order to use the cloud based mbed system.

BTW, Both the PCA10001 and the PCA10024 use a 16Mhz crystal to run the radio and Cortex M0.

Hope this helped,


Accepted Answer

Hi, Jay, thanks for your response. the board we are using is designed by ourselves. it maybe an old version(QFAAG0). i downloaded hex file directly into nrf51 flash via J-Link Debugger, it didn't work. do you mean that only the latest version chip can work on mbed platform?

posted by Yuting You 10 Apr 2014

Hello Yuting,

The QFAAG0 is the production part being shipped currently and is the device on the new PCA10024 mbed board. I took my non-mbed Nordic evaluation board and programmed it with the blinky file I created with the mbed cloud and it works as designed. (LED 0 blinking about every .5 seconds). To do this I used the new mbed compiler and then I used the Nordic PCA10001 board which uses the Segger j-link programmer IC and the nRFgo studio.

If you are having issues programming the nRF51822 over the SWD lines then I would look at something else going on with the board you made. I suggest that you submit the schematic and layout to the Nordic Semiconductor support portal located on the Nordic Website. They can review your hardware design.

Regards , Jay

posted by Jay Tyzzer 10 Apr 2014

Hi, Jay, really appreciate your patience in answering my quesion. i've solved the problem now. i used nrfgo studio and j-flash to download a same hex file respectively. nrfgo studio prompted me "Programmed Successfully application ...", but i read back program from flash(using j-flash), i found all the data is 0xFFFFFFF, i should mention that when i downloaded both softdevice and application, it worked. and then i downloaded the hex file by using j-flash, it worked fine.

i'm really happy my board can work on mbed platform, and i hope the information above can be helpful.

posted by Yuting You 11 Apr 2014
7 years, 3 months ago.

Hello Yuting,

I have meet the problem as you said,but not have solved. I used the Nordic PCA10001 board. I use following program:

  1. include "mbed.h"

DigitalOut myled(P0_19);

int main() {

while(1) { myled = 1; wait(0.5); myled = 0; wait(0.5); }


Then I download the hex file from the online compiler.I use the NRFgo studio.

First,I choose the nRF51 programming.Click erase all,than I click the program application to download the hex file into the nRF51822 chip.But there is no phenomenon.

Why?Please help me. Thank you!