Re: [avr-gcc-list] programming header, pinout?

[Richard Urwin]

On Sunday 12 Dec 2004 2:31 am, Graham Davies wrote:
> "Torsten Mohr" wrote:
> > i design a PCB with an ATMega128 at the moment.  I want
> > to in-system-program it, what is the preferred pinout for it?
>
> Yes, there are two pinouts, 6- and 10-pin.  They are documented in
> the STK500 User's Guide, which you can probably download from the
> Atmel Web site (see also below).  Only 6 pins are needed, so a
> smaller 6-pin header saves space on your board.  But, as Joerg says,
> 6-way ribbon cable and IDC sockets are not so easy to find as 10-way.

It's easy enough to find a 6-pin header with individual crimp pins. The 
10-way pin-out gives you interleaved ground wires when wired with 
ribbon, reducing cross-talk.  So I'd say it depends on what sort of 
cable you prefer, and how long it's going to be.

You can probably get polarised 10-pin sockets too, so it also depends on 
what sort of users you've got ;-)

NB. The pinout has pins 1 and 2 across the width of the pinout, and odd 
numbers down one side and even numbers down the other. IIRC that's not 
the standard numbering for IDC sockets, but it does match the ribbon 
cable.

The pin-outs are given in Atmel note AVR042.

-- 
Richard Urwin