[sdiy] Problems with AT90S8535 ISP Interface

[Paul Maddox]

Carsten,

> could anybody please help me?

we can try ....

> I built a testboard for a AT90S8535 with the simple ISP Interface from
>
> http://www.qsl.net/ba1fb/

> (PC parallel port with four resistors to MISO, MOSI, SCLK and RESET) and
> tested it with the Ponyprog software which I installed on my Windows 98
> PC.
> Everything works fine.

kewl..

> But then I testet all with my Windows 2000 Laptop, and the ISP interface
> does not work. The Ponyprog software reportet connection test failed. I
> made some tests with inverting signals, but no changes at all.

Your parallel port may need to be set to either EPP or ECP, checkt o see
which your desktop is set to and make the latptop the same.

> One obvious difference between the Win98 PC and the W2K Laptop is that
> the target device connected to the PC is permanently resetted until
> programming starts and if it is connected to the Laptop the target
> device is not resetted.

It sounds like the parallel port mode.
Also be aware that *SOME* software wont handle the NT style parallel,
Microshaft changed the way the parallel port is handled in NT4, and hence
win2k (NT5) and XP (NT5.1).
You may need to get a peice of software that can handle win2K (codevision
does as does the newer AVRStudio)

> Might there be a difference in Port Voltages / Currences between PC and
> Laptop, so should I take away some resitors or use other values?

possibly, but I doubt it..

> Is there a pin conrolling software layer between Ponyprog and the
> parallel port (firmware, operating system)?

yes, in the OS, see above

> A printer connected to the Laptop works fine.

this is because the software (printer driver) just fires stuff at the
printer port, windows intercepts it and handles it for you. The AVR
programming software tries to access the parallel port directly, something
win2K/NT doesn't like.

I would suggest two things
1) if you're serious about getting into AVRs , buy the ATAVRISP, its a
serial port dongle that lets you program *ALL* the AVR range
2) Get AVR Studio from the Atmel site
3) Have a good look around the AVRFreaks page (www.avrfreaks.net)

Best of luck
Paul
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