6 years, 9 months ago.

What's the difference between the RN-42 and the RN-42XV + Question about the baudrate

Hello everybody,

I'm a very beginner in this kind of area so don't hesitate to tell the things with a simple language :) My project is the following: I would like to control a robot with matlab. So I'm using the mbed NXP LPC 1768 card and everything works well. But now, I just want to not have a cable between my PC and my mbed card. If I understood well, that's really simple to do, I just need the to buy a RN-42 bluetooth module and respect the connectivity indicated on this page: http://mbed.org/components/RN-42-Bluetooth-Module/. So normally I don't need any second card to put on my PC if I already have an external bluetooth usb key or if my PC has already bluetooth, is it right?

But I was wondering what's the difference between:

- the RN-42 Module: https://www.sparkfun.com/datasheets/Wireless/Bluetooth/rn-42-ds.pdf - the RN-42XV Module: http://www.farnell.com/datasheets/1712626.pdf

The number of pins are not the same. Can I do the same with the RN-42XV module by just using the RX, TX, VDD and GND pins, like it's writing for the RN-42 module on this page: http://mbed.org/components/RN-42-Bluetooth-Module/ ?

Also, I'm asking myself some questions about the maximum baudrate that I can get. My mbed card can reach 921600. On the mbed website (see the link just above), it's written with the RN-42 module you can reach 115200 but in the datasheet, it's written on the first page: "Sustained SPP data rates - 240 Kbps(slave), 300kbps(master)" and on the second page: "baud rate speeds: 1200bps up to 921 kbps". t's written after also that we can program the baudrate... Do we need to program this stuf on the RN-42 module with a PC ? For that do we need an external programmer ? ... I'm a little bit lost. Actually, what I just want to do is to have a baudrate of 921600. Is it hard to do ?

Thank you very much in advance for your answers,


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1 Answer

6 years, 9 months ago.

Hi Quentin some answers to your questions

The RN-42 is the SMD component for bluetooh, in other words its the chip itself you can solder directly in your pcb and use all the pins if you want

The RN-42XV is a breakout board that uses the RN-42, and put in into a PCB Xbee like form (the pins matches with the XBEE to make the change easier), because of that many of the pins of the original RN-42 are not used in this.

Yes, you can use the RN-42XV and connect only VCC, GND, TX+, TX- to make it work

Another breakout board that use the RN-42 bluetooh chip can be found here: https://www.sparkfun.com/products/10269

To configure the RN-42XV module you have to connect to it with a bluetooh dongle (the module have to appear as COM port) and with teraterm you can send commands like enter command mode ($$$). See the document below for more info about all the commands available: https://www.sparkfun.com/datasheets/Wireless/Bluetooth/rn-bluetooth-um.pdf

And another comment the RN-42 is the low-mid range bluetooh chip is you want more range you can use the RN-41 chip breakout board available here: https://www.sparkfun.com/products/11600

If i can help you with something else, feel free to write me


Accepted Answer

Thank you very much Ney, it's very clear :)

posted by Quentin Vinckier 29 Sep 2013