Hi All,

I'm reasonably familiar with the 8051 but learning how to use a new derivative.

I used FlashMagic to sucessfully program the P89LPC9408 to toggle one of the I/O lines (P0.5) at a 1mSec rep rate. Once I get more familiar with this new chip I'll put Erik's famous "No Touch" backdoor ISP entry or UART break condition into the code.
But for now I'm trying to get this micro back into ISP mode by using the 3 pulse method on the reset line. No luck so far.

The P89LPC9408 contains a Philips LCD driver chip and a P89LPC938 in a single 64 pin package.

The datasheet says hold reset low, apply power (Vdd=3.0V), wait at least 50uSec then pulse the reset line high three times with the pulses no longer than 32 uSec wide and low not less than 1uSec. Then leave resset high and the device is supposed to be back in ISP mode.

To insure accuracy of the 3 pulses I have used an AT90C4051 micro. This micro holds the reset line of the P89LPC9408 low and waits for Vdd of the P89LPC9408 to go high. Waits 100mSec then applies three 16uSec wide pulses to the P89LPC9408 reset line (with a 16 uSec low period between pulses). An oscilloscope verifies that the three pulses are timed correctly but the darn P89PLPC9408 does not go back into ISP mode!

I'll experiment some more tonight (unless I decide to drink some nice red New Zealand wine instead) but if anyone has already gone through this experience I'm more than willing to learn from theirs.

Cheers,

Bert