I have two remote gsm switches. Their developing company has stopped operations and both the devices are now not working. I opened those devices and found onboard atmega328p paired with sim900 gsm module. There is one mini usb port that and its data pins are connected to tx/rx pins of atmega328p. I am trying to program this board with my own code to make it work again. I tried to connect atmega with ch340 usb to ttl adapter but not able to program. Can anybody please help me to reprogram this board.
Realised landed at wrong place. Please delete this question. Thanks.