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I understand, now lets hope I can remember it .

Thank you al for your support!

No offense but to my opinion ISP and ICP (should?) mean something else.

ICP (In Circuit Programming): meaning you can program the processor without taking it off the board.
ISP (In System Programming): Meaning you can program the processor without taking it out of the system. And normally that automatically means that the processor does not require the Vdd to be switched on and off.

That NXP uses hardware and software for ISP ok but it could also be that you only need hardware. Like with the Silabs processors.

Again no offense but I like to discuss items like this. And my opnion is (not) always true


 

[must]

Thank you for your reactions!

Both solutions have a downside. When programming fails it could be that the no touch code is not complete or the uart is not setup properly. In that case there is no way to reconnect to the processor anymore.

I just had contact with NXP and they confirmed that the Vdd must  be switched to get it into ISP mode (to my opinion it should not be called ISP but also ICP). So we have to decide now if we are going to continue with this processor. If we do continue, ICP will probably be used to programm the processor.

Kind regards,
  Anton Beerens

We made a development board where we use a LPC935, to program the processor on location we want to use ISP.

Now we have a problem to get the processor in ISP mode. We want to use the three pulses on the reset but do not want to switch the Vdd. We tried this on a demo board but could not get it working. The scope shows three pulses on the reset but the processor does not go to ISP mode. So is it possible to enter ISP without switching the Vdd?

We want to do this because the LPC will keep running when there is power on any of the IO pins and we do not want to use a driver for the IO.

Any suggestions?

Kind regards,
  Anton Beerens