programming nrf51822 in low voltage mode using level translator

[michel]

I'm trying to program a nrf51822 custom board using the SWD interface of the nrf51 DK. The board is using the low voltage configuration.

I'm not duplicating this question because I think that I'm showing a different problem here and I'm showing the logic level translator configuration.

I'm connecting everything as follows:

• SWDIO on nRF51 connects to SH_SWDIO (pin #4) on P20 (green wire)
• SWDCLK on nRF51 connects to SH_SWDCLK (pin #5) on P20 (orange wire)
• VDD on nRF51 connects to SH_VTG (pin #3) on P20 (cyan wire)
• GND on nRF51 connects to SH_GND_DETECT (pin #8) (purple wire)

When I try to flash program the board, the keil throws this error:

When I disconnect the ground detect of P20 the keil programs the DK board.

My question is: What am I doing wrong? Why it doesn't work as I expect?

Thank you in advance.

Best Regards.

[monpetit]

I wonder the reason that you use voltage divider instead of step down regulator. As far as I know the voltage divider can't provide power to other circuitry. Did your board use to work well? Even so, it seems that current of circuitry is not s​ufficient to be detected by J-Link debugger.

You should check the current to flow into your board.

[monpetit]

Hi michel,

You can replace voltage divider with a regulator such as the MCP1700.