Test Routine For RS232 Communication

Overview

This project illustrates the RS232 transmission and reception for PIC16F84 microcontroller, which is fully controlled by software.

Explanation

During operation, the received ASCII characters are that are sent from PC through RS232 are displayed on the LCD along with their corresponding decimal value. The feedback of received characters is sent back by the microcontroller to the terminal window. The code size is approximately 566 instruction words. A status message ‘@’ is being sent to the PC every 2.75 seconds when the PIC terminal is idle.

A dot matrix LCD display and a MAX232 for RS232 transmission is used by the PCB test board for PIC16F84. The test setup uses LCD display on PortB and asynchronous RS232 connection. The connector at the back consists of RS232 to USB 1.1. After the reset, a welcome screen of the program is seen on LCD display. The start-up message of the RS232 test routine can be seen in the screen shot of the HyperTerminal Program.

The device has a clock frequency in the hands of a 4MHz crystal with 1 MIPS throughput. The acquisition methodology is interrupt-based RS232 with LCD display and RS232 echo during normal operation.