RN-41 Bluetooth Fast Data Mode

Wireless & IoT
1

I have two RN-41 bluetooth modules, the master is connected to a dsPIC33 and the slave is connected to a PIC18.

I’ve been able to send data back and forth just fine. But when the slave tries sending too many messages the BT stops transmitting/recieving data, but the two modules stay connected. I’m trying to see if using fast data mode will fix my problem.

Here is my connection process but it seems whenever I try to enter fast data mode the RN-41 stays in command mode. Its not clear to me if the boards automatically enter fast data mode or not. The PIC18 sends the slave RN-41 a ST,255 so it can enter CMD mode at any time.

Connection Process

  1. $$$

  2. C,00066601AB26

  3. $$$ (master reenter cmd mode)

  4. F,1 (master enter fast data mode)

  5. $$$ (put slave in cmd mode)

  6. F,1 (put slave in fast data mode)

Looking on the scope it looks like I’m not getting the master RN-41 past step 4. Reading another post on the forum I got the impression the master module did not need to be put in fast data mode. So I tried skipping steps 3 and 4, but never saw the slave device entering CMD mode after step 5.

Any ideas?

Thanks