Still retained in debug mode nrf51822

[Satheeshkumar]

hi all

I am facing the issue that the chip still retains in debug mode. SWDCLK pin has connected to GND directly.

steps:

1. after flashed hex file, removed debugger from the chip and made a hard reset.

2. now my customized application has communicated with another device via UART(note: this is half-duplex communication and multiplexing UART line and power line to another device).

3.it again resuming debug mode and retain( ~1mA).

4.oftenly resetting the chip automatically.

NOTE:

1.SWDIO has connected to VDD with 10K resistor.

2.SWDCLK has connected to GND directly. I made strong GND on SWDCLK pin.

please help anyone.

thanks in advance

[Håkon Alseth]

Hi,

 

Based on this information, it is very unlikely that your issue is due to entering debug mode:

Satheeshkumar said:

sorry for late response. it was the pin reset by SWDIO/nReset pin. I have disabled all the software reset in my code.

I checked, there is no any external power up. we used bat42 diode to isolate the power to the nrf51 chip.

it is the very very huge issue for me. I have used RTC for the calendar, due to unnecessary reset,  the RTC also resetting the calendar value.

to avoid this issue, I have written the current calendar value in flash memory for every minute. even though, still persist the lagging of time.   

I am sure, the reset has happened by a chip which has changed to debug mode unnecessarily. please help me. 

Debug mode is entered if SWDCLK goes high, and SWDIO goes low. SWDCLK cannot go high, as you have directly grounded that pin.

What you are describing sounds like an assertion occurring in your application, or that you have noise in your design causing the SWDIO pin to be dragged low.

What I recommend is that you enable blocking assertions in your firmware (add the preprocessor define "DEBUG" to your project) and also check the RESETREAS register upon reboot, then update this thread with the debug information you get if one of these states occurs.

 

Best regards,

Håkon

[Satheeshkumar]

thank you for your response. let me check and update soon.