Entering ISP mode with Vdd already applied??

[Rvoogd]

Question: I'm using FlashMagic via the commandline interface to program 89lpc932A1 ISP.
My circuit with the Philips uProc doesn't allow FlashMagic (via the Keil MCB900 circuit) to switch on the power supply.
The problem is that to enter ISP Vdd must be applied with Reset (/RST) low(before the pulses on /RST are generated). FlashMagic unfortunately first makes Vdd and Reset high!! after which VDD and Reset are low during T1 and Vdd is applied with /RST low during T2.
Is there a way to force FlashMagic not to make /RST high before it is made low during T1?? That would save me from a lot of trouble while I can apply the power supply myself

Thanks!

[Andy Ayre]

When a COM port is opened, RTS and RTS are automatically set to specific voltage levels, and I think that is what is causing VDD and RTS to go high. This is part of the COM port behaviour.

[erikm]

have you considered NoTouch? that removes all thus stuff

Erik

[Rvoogd]

Hi!

Thanks for your replies. We're using the noTouch code now, works ok!
However I'm still figuring out a circuit which allows to use FlashMagic to enter ISP with the reset pulses. It sometimes happens that a microcontroller can't be reprogrammed by sending a break to start the bootloader. Then the only solution is generating the reset pulses for ISP.

Rens

[erikm]

It sometimes happens that a microcontroller can't be reprogrammed by sending a break to start the bootloader.

Then take "the backdoor" and modify it for the LPC (please post it when done)

Erik

[Andy Ayre]

For the pulse entry circuit, copy the design from the MCB900. The schematic is freely available (see the link on the Flash Magic web page).