SparkFun Forums

[lusher00]

I have a bluetooth bee from ElecFreaks based on the HC-05 chip. It doesn't seem to matter what I set the baud to in RealTerm, I can still talk to it. What's up with that? The microcontroller is talking to it at 38400.

[Valen]

... It doesn't seem to matter what I set the baud to in RealTerm, I can still talk to it. What's up with that?....

Is that a problem? I'd love to have auto-detecting baudrate devices. Those are rare though. But that is probably not what you meant. Did you mean you CAN'T connect to it at all, no matter which baudrate you set it to.

Please elaborate a bit more about how you are using this device. How you have it hooked up. To some kind of arduino? To PC? Did you try communicating with it directly over a serial port. Or tried only as wireless link to a bluetooth dongle.

I presume you found the documentation on the productpage of Elecfreaks:

http://www.elecfreaks.com/store/bluetoo ... p-171.html

[lusher00]

My "issue" is exactly as I described it. No matter what I set the baud rate to, I CAN still talk to it. Why does the device allow me to send it commands to set the baud rate if it doesn't really care what baud (or data bits, parity and stop bits for that matter) I use to talk to it on the RF side.

The serial side is a Cortex M3 talking at 38400-8-N-1.

Yeah autobaud would be neat if that's what it were doing but is it? If I send RF data at 115k how long before my buffer fills up? What about the reverse? I send it RF data at 9600 and the serial side is 115k, what's it sticking in the empty spaces while it waits for the next character?

I just want to understand the magic here

[Valen]

Ok, sorry for misinterpreting what you wrote. More often then not people don't pay attention to putting the "n't" or "not" in their posts when something doesn't work. Somehow it doesn't seem to register with them, something phonetical I think. So I expected this to be the case again.

That said, the pc would be communicating with the 'virtual serial port' of the ' bluetooth dongle in the USB port ( or built in with some laptops), so that would not be setting the RF datarate. As that is controlled by the bluetooth protocol. What you set is the baud rate between either the arduino UARt port and Bluetooth bee UART port, or the PC/Android internal serial port and it's bluetooth chip. Both ends are a serial/UART kind of interface, but what is in between isolates them and is not reliant on the baudrates you set. These can be set to different values IF you do not send too many characters so the slowest baudrate side doesn't bottleneck.