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Dear Andy ,

Thanks a Million for your help. Programming of LPC936 is like a charm.

It required only one READ DEVICE SIGNATURE push in the DEBUG mode and the LPC936 is again open to enter ISP.

Can you please confirm or correct me from wrong:

Refering to the P89LPC933/.../936 Datasheet Rev. 06 as of 20 June 2005 Fig 31 says:
Maintain at minimum waiting time of 50 microseconds before applying RST pulses. But the maximum is infinite. I understand, the Device should wait forever in order to detect the pulses.

My experience is that all five consecutively tested PLC936s give up after T1 = 220 ms. If I change in FlashMagic the default settings for LPC932 ... LPC936 for T1 (250ms) and T2 (120ms) to any lower value than 220 ms down to 1 ms entering ISP and programming works perfectly right from the beginning.

Thank you,

Johnny

Hardware review: I used exactly the same hardware for testing and programming. The LPC932s and the LPC935s were placed into the PLCC socket on the MCB 900 board first AND and in the second step into a PLCC socket at the end of a 12 cm long 10-wire flat ribbon cable. It's the same connection cable. Between the three digital signals is always one wire grounded to reduce crosstalk. As far as I can see: there is - in electrical view - no difference between the circuits.

Testing prior to programming: I have made every effort and double-checked all steps to avoid disturbances, as I know it's really difficult to replace the SMD device here. I did not accidently mix the devices up and I do not ignore warnings because of the importance of the project.
As you mentioned, Andy, I "overprogrammed" an LPC932 in the LPC936 settings with a 12kB HEX file. As expected, that device is no longer responding, and I intend to re-program it with my Keil EPM900 emulator/parallel programmer some times later.

I worked on the MCB 900 board and improved the VDD rise and fall times to less than 10 micro-seconds by adding an NPN Transistor (the emitter to ground) in parallel to the PNP device. All unused pins at the 28 pins socket are connected to VDD with 33KOhms in parallel with 470pF and the flickering of the eight LEDs has stopped.

The test devices are working any time. But still no luck with the LPC936.

I am wide open for every advise and all questions pushing me in the right direction. Thank you in advance !

Johnny

Hello!

I was able to read the device signature of the P89LPC936FDH (the response was 24H) and perform the blank check without any problems. After programming the device with a test software (it was Keil's blinky.hex file) the blinky program works as expected (full success). However I cannot re-program the device by no means with the "real" HEX file now nor does it respond any more to read requests from Flash Magic.

In order to avoid a mistake and as the the P89LPC936FDH is already rock-solid glued on the target board I tested the methodology of programming with both, the LPC932BA and the LPC935FA a hundred times successfully. After that careful examination I gave it a try: Now the P89LPC936 is blocked. I get "unable to connect at the specified baud rate ...

For further information: FM version 2.44, tried all BR 7200 kB/s down to 2400 kB/s,
"Erase all Flash" and "Erase blocks used by Hex File" was unchecked. And for sure I kept my fingers away from the Flash Magic ISP "Boot Vector and Status Bit" drop down menu.
Hardware environment: Original Keil MCB 900 board with 15 cm long wires from the 28-pins socket to the target Micro pins. Settings of T1: 250 ms and T2 120 ms. Measured VDD rise and fall times at the Micro: 0.05/0.35 ms. The digital signals Reset, TXD and RXD seem to be un-corrupted and without oscillations.

Have I killed the Micro? All assistance welcome. Please help!

Thanks,

Johnny