I bought this module specifically because the AT command manual specified that it can handle 7-bit data mode, unlike other generic cheaper BT modules.
In the manual, it appears to indicate that this can be enabled with the command S7,1
However, when I type that command all I get is ERR and it is not listed in the command list when you send “h”
Firmware version is 6.15.
How can I enable 7 bit data mode?
Please help or this module will not work for my project!
I should add that all other commands are working. I have set the parity, the baudrate, the BT name, etc… all without issue. Only S7 is giving me the ERR
I’ve seen some applications where 7 databits is only available after the parity has been configured for odd or even.
Although I was not aware of that, unfortunately that is not it. I am using even parity (which set correctly) and tried to enable 7 bit even after that. It is possible that there is some other config item that prevents enabling 7 bit, but the manual doesn’t make it very clear if there is.
I honestly just think it is not supported in this firmware even though the manual lists it and even has a section about the limitations of baud rate in 7 bit mode. I am only setting for 9600 baud.
I unfortunately cannot change to 8 bit mode on the host device I am planning to install this into.
I just did a complete factory restore and then reconfigured for 9600 baud, even parity, SPP mode, Trigger mode, and then tried S7,1. No luck.
Try using two stop bits with the even parity.
I do not see any commands to change the number of stop bits. But even if that worked, it wouldn’t work for my project. I cannot change that either in the host system (it is a Heathkit Hero JR robot).
I found the answer. It is not supported in firmware version 6.15 and only in 4.77
https://electronics.stackexchange.com/q … dule-rn-42
You would think that knowing this, they would revise their document so people aren’t buying it assuming it is one of the very few BT modules that can do 7-bit.
For others stumbling on this question with the same issue, the solution appears to be obtaining a module with 4.77 firmware. Microchip has a part number for it and Mouser sells them. However, note that it will not be a breakout board like Bluesmirf and you will need to make your own or find a carrier PCB of some sort (or maybe swap the module on your Bluesmirf). I have not found any data on how to downgrade the firmware.