Good news!

I now have the No Touch working on the AT89C51Rx2 CPUs. I am not familiar with Erik's infamous version for the Philips parts, so I am not sure if this is really No-Touch. My application software sets a flag to set up the ISP mode. I accomplish that by grounding a port pin. I then reset the board to invoke ISP. So I have to actually touch it twice...

I was using FLIP and staring at the data sheets when I noticed that the default value for BSB is 0xFF, but FLIP shows it as 00 after I run my application. I had not been resetting this back to a non-zero value, so that was preventing the built-in bootloader from running.

The algorithm is:

CLR EA
Map ENBOOT
Write 0xFF to BSB
Clear BLJB
wait for reset.

Also note that writing to the BSB and BLJB are done by setting up registers and doing an LCALL 0FFF0H. I don't know where the 0F800H addresss came from.

-- Tom Bachmann