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nimaltd / gsm_v5

gsm module library for STM32 LL
GNU General Public License v3.0
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"Enable a gpio as output and open drain to connect gsm power button" means? #37

Closed digidhamu closed 2 years ago

digidhamu commented 2 years ago

As per the instruction in README.md, could you please guide me what it means as below?

"Enable a gpio as output and open drain to connect gsm power button"

Do I need to connect GPIO to SIM800C VCC pin?

7aman commented 2 years ago

It must be connected to PWRKEY of SIM800C (pin 39). Then modify these two defines in gsmConfig.h

#define _GSM_KEY_GPIO                   GPIOD
#define _GSM_KEY_PIN                    GPIO_PIN_7
digidhamu commented 2 years ago

In this case, my board doesn't expose the PWRKEY Pin from SIM800C. I have only VCC, GND, RX, TX and RST and I could only able to power up after RST is connecting to GND.

So, how do I proceed?

7aman commented 2 years ago

It seems your RST pin has the same functionality as PWRKEY.
If you can trace it visually or using a voltmeter (buzzer mode), you could be sure if it is directly connected to pin 39 itself or to base of a transistor that its collector is connected to the pin 39.
Or ask the manufacturer or seller.

7aman commented 2 years ago

image

digidhamu commented 2 years ago

Thanks @7aman. I could now able to use RST as PWR_KEY and see working!