No Subject

[jfox@xxxxxxxxxx (Jeff Fox)]

Dear MISC readers:

Dr. Ting has announced that tests have confirmed a "feature" in
the plastic MuP21 chips.  It appeared that there was a problem
with the A! instruction in the boot code, and with the A! 
instruciton in DRAM at lower voltages with the plastic packages.
Dr. Ting had some of the production die packaged in ceramic dips
like the prototyped chips to test the die.  They work perfectly
in the ceramic packages.
In the plastic chips the extra inductance in the package seems
to cause a problem with A!.  Chuck modified the boot code to not
use A! and has said that  A! will work properly at low voltages
on the plastic chips if it is in the first slot, or is preceeded
with a NOP.
The P21Forth includes a disclaimer that version 1.00 will only
run above 5.4V on the plastic chips.  I will create a 1.01
that will run at lower voltages on the plastic chips.
Jeff Fox
Ultra Technology