Issue with LPC2368 ISP.

Hi geeks !

I am struggling with a strange issue in LPC2368 ISP circuit.

I have two different boards of LPC2368 with different layouts.But both
of them have same circuit for ISP through UART0 and using FlashMagic
for programing.

The issue is, the ISP circuit works only on one of the boards.On the
ISP non-working board, the processor doesnt respond to the RTS and DTR
signals.

Whats making the situation more strange is , the ISP works fine if I
force the LPC2368 in ISP more manually, that is , using push buttons
on RESET and EINT0.


So, to summerize , one of the board's ISP is not working with RTS and
DTR signal, while it works manually.Also the same circuit with RTS and
DTR works of a different layout.

So....geniuses......any clue ? any suggestion ?


Thanks.
Nik

"nik" <nitinkothari@gmail.com> wrote in message 
news:da3f0879-ac9f-4641-bf44-64558451acce@r37g2000prr.googlegroups.com...
> Hi geeks !
>
> I am struggling with a strange issue in LPC2368 ISP circuit.
>
> I have two different boards of LPC2368 with different layouts.But both
> of them have same circuit for ISP through UART0 and using FlashMagic
> for programing.
>
> The issue is, the ISP circuit works only on one of the boards.On the
> ISP non-working board, the processor doesnt respond to the RTS and DTR
> signals.
>
> Whats making the situation more strange is , the ISP works fine if I
> force the LPC2368 in ISP more manually, that is , using push buttons
> on RESET and EINT0.
>
>
> So, to summerize , one of the board's ISP is not working with RTS and
> DTR signal, while it works manually.Also the same circuit with RTS and
> DTR works of a different layout.
>
> So....geniuses......any clue ? any suggestion ?
>
>
> Thanks.
> Nik

Check the JTAG signals that are active inputs on  RESET.

1 or more of theses need tobe pulled high or low to revent from JTAG 
activity before code execution from  0x00000000

Joe

In article <da3f0879-ac9f-4641-bf44-
64558451acce@r37g2000prr.googlegroups.com>, nik says...
> Whats making the situation more strange is , the ISP works fine if I
> force the LPC2368 in ISP more manually, that is , using push buttons
> on RESET and EINT0.
> 
> 
> So, to summerize , one of the board's ISP is not working with RTS and
> DTR signal, while it works manually.Also the same circuit with RTS and
> DTR works of a different layout.
> 
> So....geniuses......any clue ? any suggestion ?
> 


Double and triple check RTS and DTR haven't been swapped (scope the 
lines).  I've seen people swear up and down that they had checked these 
and they were right only to eventually realize thay were swapped.

Robert
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