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I Built My Own 8051 Board And It's Not Working, HELP!

I Want To Build My Own EPROM/87C51 Programmer, Do You Have A Schematic?

If you don't have an EPROM programmer, usually it is
best to buy an EPROM programmer than try to build it yourself.
This is due to the fact that it's difficult to troubleshoot
your programmer without being able to write known data
into chips and read chip you're attempted to write with a
known good programmer.  Without an existing programmer, a
significant number of "expendable" chips are often needed,
and this cost is often overlooked in the decision that it
costs less (or it might be fun) to build your own.

The 8051 development board from our website is designed
so that once you have the board, no EPROM programmer
is required.  This is done with a flash chip on the board,
and the pre-programmed 87C52 chip supports download and
automatic start up of your application from the flash
memory.  This inexpensive board provides both the board
to develop your application, and an on-board programmable
permanent storage of your finished application.  However,
if you want to program the 87C52 itself, you will need an
EPROM programmer with support for the 87C52.

If all you need is just one chip programmed with PAULMON2,
you can buy just a single chip from us that's already
programmed.  Here's the page:

http://www.pjrc.com/store/87c52.html

The programmer I use is an EMP-20 from Needham's Electronics:

http://www.needhams.com/

There are many other lower cost programmers available on the
market, but they typically support far fewer devices.

TODO: list of low-cost EPROM programmers that support the 87C51.

If after reading all this you still want to build your own
EPROM programmer, there are a few resources on the net.  The
rest of this section assumes you want to program 8051
compatible microcontrollers.

Probably the best approach is to use the Atmel 89S8252 chip,
which features an 'in-circuit' serial download that
requires connection to only a few pins.

PROG8252 is a free program that can write to the 89C8252
using a PC parallel port and a small circuit that requires
just one 74HCT126 chip.  Unfortunately, the original web
site appears to have vanished, but searching for "PROG8252"
may turn up some useful information.

AEC Electronics appears to have a similar freeware 89C8252
programmer.  Their website is:

http://www.aec-electronics.co.nz/

Atmel has an application note that describes a parallel port
based programmer that requires a handful of standard logic
chips.  The URL is:

http://www.atmel.com/atmel/products/prod72.htm

Beware, I have received two reports from students who
attempted to build this design and could not get it to work.

Years ago, I designed a programmer that would write 89C2051
(20 pin Atmel 8051s), with an in-circuit feature, where it
would connect the chip to your board through a ribbon cable.
Of course, there's the chicken-and-egg problem, in that
my design used an 89C52 (40 pins).  I had the benefit of a
working programmer when I made this design.

Here are two other programmer projects available on the net,
which can write the the 89C52, but both also suffer from the
chicken-and-egg problem, in that they have pre-programmed
microcontrollers in their design:

http://members.fortunecity.com/ucontroller/easy2/easy2.htm
http://www.specs.de/~danni/tools/proflash/index.htm

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