Micro-controller Programming
MAS.863 -- Fall 2003

Notice

Assignment

Coding

Burning

Serial Transmission

Sample Codes

Applications

Resources

PIC Micro-Controller Serial Transmission:

1. Connect your board to a serial cable

2. Make sure that the PICSTAR PLUS DEVICE PROGRAMMER window is not open

3. Open SecureCRT or Hyper Terminal, and make a new serial connection with the following properties:

Protocal: Serial
Port: COM1
Baud Rate: 38400
Data Bits: 8
Parity: none
Stop Bits: 1

4. Connect

5. When you press your button on your board, you should see "HELLO WORLD" or whatever you chose to write come up on the screen at least once. If not, then it may have to do with your code more than some other error. Make sure that you are using RS232 protocal, not RS485, like Raffi's sample code.

A message from BB2 about connecting serial ports and stuff:

 

Date: Thu, 13 Nov 2003 03:36:02 -0500
From: Ben Buchwald <bb2@MIT.EDU>
Subject: Re: errata on the board design

It is a confusing situation. the ground pin is 5. the transmit and recieve pins are 2 and 3, not 3 and 4 as orinally in the plans. However, the layout on our boards is for a female DB9 but we actually have a male. Not only does that mean the pins are mirrored, but it means that tx and rx are reversed (device side vs. host side issue). So not only are the tx and rx pins shifted but also reversed which has the effect of mirroring them, which, coincidentally the footprint already is. Sometimes 3 wrongs do make a right, it seems, almost.

IMPORTANT NOTE:
The use of male DB9 connectors on our boards makes them a host, as is the computer. Therefor, for two hosts to talk to each other, when you connect your board to the computer serial port you must use a null-modem which crosses over the transmit and recieve lines. This will be obvious because a standard serial cable is female (host side) to male (device side, like the PICStart). In 023, there is a null modem cable on Raffi's workbench. It is a female to female cable and the ends say "null modem" on them. If you unplug the serial cable from the PICStart, you can plug the two cables together. To connect to your board open up SecureCRT with the COM1 profile with the correct baud rate (if you don't trust the baud rate in the title, check the preferences to make sure someone hasn't screwed around with them).