BT module "fast data mode"

Wireless & IoT
1

Just a quick question to make sure I’ve got this figured out correctly:

I’ve got two of the older Mitsumi-based bluetooth modules (WML-C40AH using the BlueRadios serial module ATMP firmware). I need to enable fast data mode between a PIC18 and the BT module, so the PIC sends the following data on its serial port:

atucl (place the local BT module in idle mode)

(100ms pause)

atdm,####<BT.ID>####,1101 (master connect to remote <BT.ID> as SPP)

(100ms pause)

atmf (enable fast data mode on remote BT module)

I get that atmf causes the BT firmware to stop parsing the data stream for any AT commands, which allows for much faster throughput. But the documentation says that it will only work when already connected. Now, in my above sequence, after I connect, I am then sending AT commands to the remote device (slave), so I guess I’m telling the slave to enter fast data mode. The master is already connected, so it is by default in fast data mode because you have to enter “+++” to drop into command mode. Is this the correct interpretation? Can someone confirm, or set me straight?

Thanks!

2

I was not enabling fast data mode on both the local and remote BT unit. The proper sequence, in case anyone else is wondering (and don’t forget at least 100ms pauses between commands):

	atucl<cr>	//place the local BT module in idle mode

	atdm,####<BT.ID>####,1101<cr>	//master connect to remote <BT.ID> as SPP

	+++<cr>	//places master in command mode while still connected

	atmf<cr>	//enable fast data mode on master, any further commands
			     //will be ignored and sent over the air to the slave

	+++<cr>	//passed on by master, places slave in command mode

	atmf<cr>	//enable fast data mode on slave

Now that I know this works, it all seems simple and straight forward, but it took a while to figure it out exactly what was going on. Got up to115200 bps from my PC, and had a PIC18 streaming at 500k!