BASIC Language RS232 Serial Communications Program

by Malcom Kemp
April 3, 2000

This program was written to facilitate the development of a communications program for the PIC microcontroller. The overriding criteria were to be able to deliver precise 8-bit values to the PIC over the RS-232 Tx line, and to receive and display precise 8-bit values from the PIC over the Rx line. This program was developed from a program that Adam Davis made available through the PICLIST (PIC microcontroller discussion list).

The USART on the PC can be explicitly controlled through the “Settings” menu selection. When any of the Port, Speed, Data Bits, Parity, or Stop Bits selections are changed, the port is disconnected, the change made, and then the port is reconnected, if it was open to start. There is a small chance that data may be lost in this transition. It is expected that the port will be set to the proper operating parameters before the port is connected.

The “View” menu selection will set the display of the output string and the response string to either an escaped ASCII, or to a hex display. The hex display is a two character hex representation of each byte separated by a space. The ASCII display displays printable characters, but will escape non-printable characters with a “\” character as follows:

The output string can be edited at any time, just follow the rules of the display. For the hex display, the hex characters must be space delimited. The field will be read, edited and rewritten when you leave the field. Be sure what is written back is what you intended.

The “send” button will transmit the output string out the RS-232 transmit of the selected port.

The “clear” buttons can be used to clear the contents of the output string or the response string at any time.

Although there is a limited space for display of the output string and the response string, they can actually be very long. The cursor is left at the right end of the string, but you can use the “home”, “end” and arrow keys to view portions of the string that may be hidden.

The file BasicCommSource.ZIP has the source files, the .exe file, and the readme.txt file.

If you find any errors in the program, please let me know, and I will attempt to fix the bug.

Also:

• RLC-1 RS232 TTL 3-5V Level Converter in a DB9 backshell
• RS-232 / I²C-Adapter & Parallel I/O Module

Questions:

• STOPspamtech.fan99SPAM at spamyahoo.com asks:

  Guan Asks:
  
  I couldn't install it and just got a message:MSCOMM32.OCX missing or errors. After check my system, I had same file and same version. Actually I can set to Hyper terminal on COM1. Does anyone have same problem or how to fix it? Thanks! My e-mail is:tech.fan99@yahoo.com

• STOPspamploutoninaSPAM at spamyahoo.gr asks:

  hello everybody.i have made a led flasher (8 leds flashing in 5 different ways using 5 switches (the programm exist in http://www.interq.or.jp/japan/se-inoue/e_pic6.htm).Does anybody know how i can replace the switches with the numbers 1 2 3 4 5 from my arithmetic keyboard of my computer? (i know i must use RS232 but i have no idea how)

• STOPspammartignago2001SPAM at spamyahoo.com asks:

  Hi! I would like to know if you can help me about USB communication with PIC microcontrollers.
  Where can I find usefull information about this?
  For USB communication, I need some special PIC (like 18F...) or can I use any PIC to USB communication?
  Tanks in advance,
  Edson.

• Daniel asks:

  This code is great, I like to use the code for my PIC project which requires me to send 8 bits at a time, but I dont know to extract which part of the code to do exactly that? Will Mr Malcom Kemp or any kind soul out there willing to help. Thanks in advance!!! My Email is Fire__ball@hotmail.com Daniel

Magdas Emilian Catalin Says: " This code is cool. Thank you very much! " +

Comments:

• God Bless this place! This was exactly what i needed thanks!+

  .