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

[Turbo J]

The "debug mode" can only be switched OFF by a power cycle or the debugger itself.

For the JLink commander, I use the following commands to switch debug mode off:

if swd
speed 2000
connect

readDP 1
writeDP 1 0
q

First 3 lines are to connect to the chip. After executing these commands you should see a drop in current consumtion.

Note that enabling the UART would also cause about 1mA current consumtion, as this requires the HFINT or HFCLK to be up and running.

[Satheeshkumar]

thanks for the response. after UART communication, the chip successfully executes sleep function. but it still retains 1 mA, even though I had disabled UART function before sleep there is no any HFCLK module running. And also the chip has reset sometimes automatically. this is purely debugging mode issue. 

[Håkon Alseth]

Hi,

 

What is a hard reset? In order to exit debug mode, you need to either power cycle, or use "nrfjprog --pinreset".

Normally, the current consumption is 1.2mA when you're in debug mode. Are you seeing exactly 1.0 mA?

Does the current consumption change if you disconnect the UART connection going from the nRF to the external device?

 

Best regards,

Håkon

[Satheeshkumar]

yes exactly,  (~1.214mA) current has retained. at that time j-link was not connected 

[Turbo J]

Did you leave the UART connected? This can reverse-supply the chip via the RX pin, and could prevent the POR because VCC never drops low enough.

Remember that UART idle is HIGH.