Page Sponsored by 
Back to Victorian University Electronics Intranet Home Page Mirror.
Construction of a switch led board.

Although this board is not necessarily needed for your project in this module, it is a useful board for testing and is used in my sample programs wled.asm  bittest.asm. This program demonstrates how to output to a port and how to read a switch.

This board could be made using vero board, however Dontronics makes a board that does the job, a DT203


  1. When using this board with a 2051 it is only necessary to populate the centre bank of leds and resistors and the centre ULN2803. This is because these leds are connected to port 1 and the 2051 only has port 1 & 3. Port 3 will be used for other things.
  2. It is not actually necessary to use a buffer to drive a led with the 2051 as each port pin can sink 20mA, to a total of 80mA for the chip. Therefore if you wish to drive 8 leds at a time the buffer is a good idea.
  3. For the BITTEST.ASM program I have wired the top left push button switch to port 3.2. You can see the wire wrap wire in the photo.

Photo showing a DT004, DT104 & DT203 board use for the sample programs WLED.ASM & BITTEST.ASM

If the DT203 board is used in conjunction with the DT004 Simmbus board you can also carry out experiments driving leds and reading switches from the parallel port of your computer.

Copying these pages:
Back to Victorian University Electronics Intranet Home Page Mirror.

DonTronics Links:
Home Products Prices Directory Order Contact New Books Files Links FAQ