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Re: STM32 F407VET6 SIM800C V2
Posted: Thu May 13, 2021 1:02 am
by hobbya
You may also check the power supply. GSM module can take 2A peak current during transmission, especially during the network search. As stated in the datasheet you need large value capacitors connected at the power supply. Not sure if your Arduino board has a bigger capacitor than your STM32 board.
Re: STM32 F407VET6 SIM800C V2
Posted: Thu May 13, 2021 8:45 pm
by Orion1398
hobbya wrote: ↑Thu May 13, 2021 1:02 am
You may also check the power supply. GSM module can take 2A peak current during transmission, especially during the network search. As stated in the datasheet you need large value capacitors connected at the power supply. Not sure if your Arduino board has a bigger capacitor than your STM32 board.
I use Li-Po battery to supply GSM module.
But Thanks for idea!
Re: STM32 F407VET6 SIM800C V2
Posted: Sun May 16, 2021 6:59 pm
by Orion1398
Hi!
Everything works!
I use logic level converter, and try work whit SIM module using 5v logic.
TLL -> 5V
RX 3.3V (STM) -> LLC ->TX 5V (SIM)
TX 3.3V (STM) <- LLC <-RX 5V (SIM)
Most likely, there was a problem with TTL on the SIM module, and correctly work only 5V logic.
Thank you all very much, and I went to make a menu for that thing) 
Re: STM32 F407VET6 SIM800C V2
Posted: Sun May 16, 2021 8:32 pm
by fpiSTM
Nice. Thank you for the feedback !