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Hi all,

I am new to this forum and offcourse I do have a question.

I have made a pcb with a 89lpc935 on it. This uC should
be programmed by means of ISP. I have shameless copied
the mcb900 circuit and adapted it at some points to counter
negative voltages produced by the PC serialport. The dtr and
rts line do control resp. the power and reset line.
I put some LEDs on the pcd to see what is going on.

Now the problem : I can not initialize the flash embedded
bootloader anymore. Apparently the first time it worked
and I could program (some non working) code into flash.
But now it is dead even when I manually try to get the lpc935
into bootloader mode. No reaction after sending "U" :-(
So the bootvector and or the bootstatus bit is upset.

In my trials to get things working again I noticed the LED which
is connected to the rts (reset) line. It does not toggle three
times after pushing the start button in FM. This also goes for
the LED which is connected to the rxd line (data from the PC).

Is this observation correct ?

Is there another way to get the bootloader going except for
the notouch method ?

TIA,

roelof