Post by thread:2 Serial ports?

Dear Gurus, I'm designing an application using a PIC16F877A that communicates with another component (a gps module) through two serial pins (Rx/Tx). What I would like to do is receive gps messages in the PIC, do some processing and output them to a MAX232 that will connect to a PC. Having said that, I have two questions that are intriguing me: 1) In the PIC datasheet, I only see RC6 and RC7 as serial ports. In this application, I will need two ports, one to communicate with the GPS module and another to communicate with the PC through a COM port. How can that be done? 2) The GPS serial port operates at 1.8V levels. Can I still connect it pin-to-pin with the PIC or do I need a level shifter in between? What is the voltage used in serial communication by the PIC16F877A? I tried to look at the PIC datasheet but I got even more confused. Help please Cheers Padu ___________________________________________

Padu, You can bit-bang the second serial port using routines freely available on the web. (Alternatively, select a PIC with two USART modules!) You will need to level shift the PIC pins to 1.8v for your GPS - are you sure the interface is 1.8?, if it is say 3.3v logic then you can use a PIC 'LF' part that will run at 3.3v, and do away with level translation. Peter Moreton > {Original Message removed}