Saturday, August 16, 2008


A standard serial interface for PC, RS232C, requires negative logic, i.e., logic 1 is -3V to -12V and logic 0 is +3V to +12V. To convert TTL logic, say, TxD and RxD pins of the microcontroller thus need a converter chip. A MAX232 chip has long been using in many microcontrollers boards. It is a dual RS232 receiver / transmitter that meets all RS232 specifications while using only +5V power supply. It has two onboard charge pump voltage converters which generate +10V to -10V power supplies from a single 5V supply. It has four level translators, two of which are RS232 transmitters that convert TTL/CMOS input levels into +9V RS232 outputs. The other two level translators are RS232 receivers that convert RS232 input to 5V. Typical MAX232 circuit is shown below.


Amed said...

thanks for this post. now i'm going to work with MAX232 in joining my pc (laptop) to gsm, for repairing purpose. So i wll be glad if u can help me find tutorial, ebook, or anything that can help me understand more about this component and its application in connecting cell phones to computer. THANKS IN ADVANCE. I'm waiting for you reply. my email:

hirmus said...

i am doing pc to pc laser communication as my final year project. if you send me c, c++ code for it, i shall be very thankful to you.