HM10 BLE 4.0 Send AT Commands instead of passing through serial
When I send any commands to the HM10 BLE Bluetooth module, it sends the commands through bluetooth instead of the HM10 module processing the command. For example, I expected to send AT and have the module respond with "OK", but it sends the text "AT" through the bluetooth connection. I have tried sending the command with no bluetooth connection and the same thing happens. I have also tried sending the command via bluetooth instead of the serial connected to the device and I get the same thing.
Answer
When HM10 is connected to remote ble device it is in transparent mode. To put it into AT mode you need break connection or not establish it at all. For breaking connection use reset/break pins. Reset is 12 pin and Break seems to be 23 pin. It has sense to look IMME parameter of the module (page 32 of datasheet).
IMME Query/Set Module work type
1: When module is powered on, only respond the AT Command, don’t do anything. Until AT + START, AT+CON, AT+CONNL commands is received.
0: When power on, module will start work immediately Default: 0
Also be carefull with strings endings, usually string doesn't need to be terminated with any symbol at all: AT, but some H11 need the string to end with CRLF: AT\r\n