Hi,
I am using nrf51822 chip for BLE application. In my circuit, I have used circuit supervisory components which is resetting the MCU whenever voltage level goes below 1.8V. the output of the circuit supervisory is connected with SWDIO pin and SWDIO pin is pulled up explicitly. this is the conventional one by using us.
Now, I am trying to use BOR(Brown Out Reset) instead of this. I studied BOR usage, which is performing same operation as implicitly. I had hoped this is going to replace the external component. But it doesn't do like what we were expected. we have done some test and got failure result. following steps that what I have done here,
Done simple program no LED, no peripherals and no Bluetooth. Just made the program with sleep mode code with running of RTC1.
1. Flashed the program into MCU.
2. Connected power supply to MCU with Ammeter.
3. Turned on power supply with 3V, Ammeter is showing 3.5uA.
4. I was starting to reduce the voltage from 3V to 2.9, 2.8, 2.7 etc and Ammeter is showing ~3.5uA.
5. Finally, reached 1.8V and Ammeter is showing ~3uA. still on sleep mode.
6. Changed voltage to 1.7V and Ammeter is showing ~3uA. still on sleep mode. Not moving to reset mode.
7. Changed voltage to 1.6V and 1.5V also and Ammeter is showing ~3uA. still on sleep mode. Not moving to reset mode.
8. Change voltage to 1.4V and Ammeter is showing ~2.9uA. still on sleep mode. Not moving to reset mode.
9. Then(at 1.6V and 1.7V), turned OFF the power supply and turned ON again and Ammeter is showing ~550uA. Now it is on Reset mode.
10. MCU in Reset mode at 1.7V (550uA), increasing the voltage to 1.8V then the MCU is returned to normal sleep mode and ammeter shows ~3uA. Increasing more voltage to further level like 1.9, 2.0 etc. The chip is retaining the normal sleep mode.
The test has been conducted with N51822QFAAH1 and N51822QFACA1 series of MCU chip. Used DC/DC circuit type.
The above test has been done actual functional firmware also. The firmware function is normally in sleep until get any external interrupt.
Please any help me to clarification.
