So I got two HC-05 modules and tested them, both worked in slave mode. Then i tried to change one of the module to master mode (my module has EN pin instead of KEY which was not connected so I soldered it). So I connected the module to my arduino uno and held the EN pin high and applied vcc to the module. It entered AT mode and i could change the name and check version, set it as master. But the problem arose when I took out the power from arduino, removed the EN pin and connected back the power. The module's led didn't blink as it does when waiting for pair, it doesn't even turn on. The module receives power and i can enter AT mode again and the led blinks (once per 2 seconds) but i can't get into communication mode. And this has happened after i entered AT mode before they worked properly. Please help!
It does sound rather like user abuse. If the end pin is labelled En, the board may be a ZS-040. This has a button switch and no soldering is required.
Thanks for the reply
There was no button switch, though there is some space on the board for the button. I don't know what board it is on the back it's just written as FC-114. And if it was user abuse I should have had not been able to enter AT mode again. The button does the same thing, it connects the EN pin to vcc so it should be the same thing, shouldn't it?
The fc-114 modules use a different firmware and AT mode works in a slightly different way. The HC-05 and HC-06 fc-114 modules I have have the same firmware. The only difference is the button switch and two missing pins on the breakout board.
Have a look at
hc-05-fc-114-and-hc-06-fc-114-first-look
hc-05-fc-114-and-hc-06-fc-114-part-2-basic-at-commands
hc-05-fc-114-and-hc-06-fc-114-part-3-master-mode-and-auto-connect
this actually helped. i had connected the en pin to ground and thats why the module disabled. seems silly now that i know what i was doing wrong. thanks for those links it helped