I have a XB24 module and was wondering how do I connect it directly to a RS232 on a breadboard w/o using the circuit provided by maxstream. I was informed that I would require a MAX232 IC chip. Also RS232 has a +/-12V and XB24 has a 3.3V May I know how do I connect it so that I could balance the voltages so that it wouldn’t damage my XB24 module.
Thank you
You just connect it directly to a UART on a microprocessor. No level translation is required. Your micro needs to support the same voltage levels as the XB24 does which is usually the case when both the micro and the XB24 are running at the same voltage.
The XBee has a 3.3V UART and RS232 is +/- 12V as you have noted. The way to connect the one to the other is by using an interface between the two. This interface will level shift the voltage on one into the voltage of the other. The way this interface is created is most easily done using the MAX232 chip. You can use the MaxStream refernce schematic to create your own interface if you’d like:
http://ftp1.digi.com/support/images/XBIB-R%20schematic.pdf
If you are connecting to a microcontroller you can do as the other poster suggested and remove the RS232 and just connect UART to UART (as long as they are voltage compatible UARTS of course).
There are also various ways to interface a 5V UART to a 3.3V UART, but if there is a difference in the UART levels, then an interface between the two must also be created to maintain compatibility between UARTs.
I am trying to use a MAX232 chip to connect them. However can you explain how is it done by using a max232 chip. The schematic makes me confused, it would be great if you could explain better. Thank You.
Hi. What type or microcontroller do you use? PIC microcontroller (for example) supports 3.3v, so you can connect directly the uart (with tx and rx only it works). For connect it to a computer you can use the same scheme with 3 lines (don’t forget the ground), but for a firmware update you cant use the MAX232, you need a 3 lines RS232 adapter (MAX223 for example) for the RX, DTR, RTS signals goes to the Xbee module, only TX goes to the PC.