If you are done with UART between two micro-controllers, I am sure you would like to move on and try and communicate with a computer.
Communication with the serial port of a computer, however is not so straight-forward, since the logic system of the serial communication line differs from that of the micro-controller. The difference is basically in voltage levels. RS-232 is a method for porting the micro-controller logic to serial port logic. Read up on the background of RS-232 for understanding properly.
So, for this, you need a module which will connect the micro-controller and the PC and regulate data communication.A Max-232 chip is the one which converts the logic levels. Lots of circuits are available for it on the internet. You just need to run an image search for “max 232 circuit” or “rs 232” or similar. Here’s the link to the circuit which I used.
Here’s the image:
For making this module, use the following :
1. Right-angled DB9 female connector
2. A millimeter board made especially for the above connector
3. A Max-232 chip and mount
4. Miscellaneous connectors and wires.
All the above are easily available in the market. Try to use them for convenience,especially the first two.
Here’s how my finished module looks like :
Note the two holes on the board and the wire coming out. I purposely looped the wire once like this, because I have seen soldered connections break off due to pulling while use. The loop and the tight wires help to prevent that. Also, try to keep the wire a bit long, so it is convenient to connect it with your MCU.
Well,this is all you need. I will deal with the actual communication part in the next post (once I am done with it myself ).