Choose the best form for going into the ISP mode (p89lpc935)

[didac]

Hello,

I have finished one design, and I have a dude.


What is the best metode for going into thr ISP mode for P89LPC936, or P89LPC935?

I know what there are in the datasheet, the three pulses for RST. but i have read about notouch, and i don't know what is the best.

How do i use the three pulses(RST)?¿? I don't have any kit for programing, only have my board and the computer.

I need do more tests and i need program the uC more times.

[Andy Ayre]

If you have completed your design and programmed your device, and now you want to get it into ISP mode...

The three pulse method for ISP only works if you have the necessary circuit. You could try hooking an MCB900 up to your target hardware to "add" the circuit, but whether that works depends on your target hardware design.

ICP also requires changes to hardware

No touch and break entry require support in the firmware. If you didn't add those then you can't add them until you get the device back into ISP mode.

Andy

[didac]

I have a circuit that creates this signal, but the devices don't go into the ISP mode, when i send this signal to PIN (6) of Reset, the device don't do anything.

Can it be because the signal is wrong?

If I do the correct signal, and send this signal to the pin, the devices go into ISP mode??

In this moment, I have my design with P89LPC935, and other board that create the RST signal also design for me.

What do you recomend me?

[Andy Ayre]

I recommend you read the datasheet for the exact specification of the three pulse reset signal. It has minimum and maximum timing requirements. Use a scope to confirm that you reset and VDD waveforms match the specification.