[En-Nut-Discussion] Could not enter programming mode

[Andre Riesberg]

Daniel wrote:

>Hi.
>
>While I was programming my Ethernut 1.3 with stk500.exe, I had connected 
>SCK (SPI Bus Serial Clock) to GND. After that I read, that I must not do 
>that.
>Now stk500.exe tells me, that the controller "Could not enter 
>programming mode".
>
>Any advise how to fix it up?
>
>Thanks,
>Daniel
>_______________________________________________
>http://lists.egnite.de/mailman/listinfo/en-nut-discussion
>
>
>  
>
Hi Daniel,

do you pull the SCK signal to GND only on the programmer or on cpu or on 
both?

Do you have disconnected all power supplys and start again?

Please make some tests:
First, disconnect programmer and CPU.

- Check the SCK signal at the programmer: In normal condition (no 
programming) the signal must be on high level.
- Check the SCK signal at the CPU board. Normally you see a low level. 
With a 10k resistor to +5V you can pull this signal to high level.
- With still disconnected board try to start programming (I use 
avrdude). With a scope you can see (for a short time) a lot of pulse on 
the SCK line.

Does this work?

Greeting
Andre