[Sussex] A Little Hardware Help

[Steve Dobson]

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Hi All

I've been a software engineer for the 30 years, but I now find that I
want to learn a little hardware too complement it.  Computers are only
useful (fun) when the are doing something.  And being able to physically
interact with the world around them is an area I would like to explore -
just for fun you understand.

To that end I've started playing around with the PIC16F628 [1]
micro-controllers - a small but complete computer on an IC.  I also
found a nice set of hardware & software tutorials [2] to learn from and
have bought some breadboarding hardware to play with.  My first goal is
to get the PIC to control a seven segments display (common anode) and to
that end I have built a simple circuit[3] based on the main board [4].
Unfortunately my first attempt doesn't work!  :-(

If I remove the IC and jumper the -ve line to the seven-segment display
lines then the LEDs light up - so that part appears correct - and it
matches the circuit in the tutorial [5], although as I have a single
digit seven-segment display I have connected the 8 pins of the PIC to
the 8 inputs (seven segments + decimal point) of the display and omitted
the transistor parts.

I guess that the problem lies in the power input to the chip.  I'm using
a Bandridge BE-516 mains transformer (regulated) to provide the power,
but do I need any form of circuit on this supply, and if I do what?  Of
course I am completely clueless at this point as to how to find out what
is wrong.  I know the PIC isn't blown because if I place it back in the
programming/test board it works there perfectly.

Any and all help gratefully welcomed.

Steve

[1] http://ww1.microchip.com/downloads/en/DeviceDoc/40300C.pdf
[2] http://www.winpicprog.co.uk/pic_tutorial.htm
[3] http://www.syscall.org.uk/simple-circuit.jpg
[4] http://www.winpicprog.co.uk/pic_tutorial_main_board.htm
[5] http://www.winpicprog.co.uk/pic_tutorial_7seg_board.htm
[6] http://www.superfi.co.uk/index.cfm/page/moreinfo.cfm/Product_ID/1023

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