I upload code into arduino nano using a self-made PCB with bluetooth using this method. I was initially using Arduino Nano (chinese Clone, the one with CH340G) and Bluetooth module HC-05 (version 3.0) (Lets assume this bluetooth is BT1)
At command response for BT1
AT+NAME? +NAME:H-C-2010-06-01 OK AT+POLAR? +POLAR:1:1 OK AT+VERSION VERSION:3.0-20170601 OK AT+UART? +UART:9600,0,0 OK
All the things were working perfectly till the new nano as well as latest version of bluetooth arrived.
Bluetooth problem: I was trying to configure the newer bluetooth BT2 and I faced the error highlighted in code.
AT Commands response for BT2
AT+NAME? +NAME:HC-05 OK AT+VERSION? +VERSION:4.0-20190815 OK **AT+POLAR** **ERROR:** AT+UART? +UART:9600,0,0 OK
The problem I am facing is I am unable to change the state pin with AT+POLAR command. I think this version of bluetooth has different AT Commands. If anyone knows about this particular problem please help.
Also I tried uploading code using old bluetooth to a newer version of Arduino Nano (New bootloader OPTIBOOT) and it was successful. Needed to change the baud rate of program as well as Bluetooth to 115200.