Hardware reset for nrf9160

[Rkidechaa]

Hi,

we are developing one prototype where we are using two MCU for different task. we are planning to give common reset button (for customer access) for both the MCU using PMIC. But in nrf9160 i can see only nRESET pin which connected to SWD connector.

Question:

1) As I we are using the common reset connection while flashing the code to nrf9160 through SWD will reset other microcontroller too ?

2) can you suggested other hardware implementation for nrf9160?

3) if I use two different diode in path of reset to both the controller will solve issue?

if you see above circuit, they used MOSFET circuit between RESET and nRESET. can we connect RESET to nRESET directly?

is it necessary to connect RESET to nRESET ? can we burn program via SWD with using SWD pin?

Thank you in advance.

Regards,

Rahul Kidecha

[Rkidechaa]

Thanks  you for reply ketiljo.

ketiljo said:

It's fairly unusual to have a active high reset pin, so check the other MCU again. It's possible that you can just connect them together.

I guess I forgot to mentioned that PMIC gives active-low reset output (PFN2). when we press switch SW1(connect to ground) connected to pin PFN1. 

currently we connected PFN2 pin directly to RESET pin of Max32630 MCU. so when we press SW1 it give active output to RESET rest of the time it gives 1.8V due to pull up resistor.

I feel we can connect PFN2 pin to reset pin of nrf9160. But need to confirm that is it necessary to use MOSFET circuit or connect it directly?

Just refer above circuit for your reference.

Thank you. 

[ketiljo]

If VDD_GPIO to the nRF9160 and VDD to the other MCU have the same voltage, you can just connect both reset lines to the PMIC. If not, you need a level shifter. The nRF9160 have an internal 13 k pull up resistor to VDD_GPIO.