Thanks for the suggestions. I tried the 'RAM' command and it does not make any difference. I found the values $02 and $00 at 13h and 14h and 0 at 2002h, as would be expected.

Since this board runs at 18.432 MHz and the chip runs at double speed (6 clock cycles), I thought maybe it was too fast for the RAM (even though it is a commercial development board). So I tried lower frequency crystals down to 4MHz (resetting each time so it would recalculate the baud rate). At 4MHz, there was a noticable delay (a fraction of a second) when I hit return after typing in a test program line - but still the exact same results.

Here is something else interesting I noticed in immediate mode:

*MCS-51(tm)BASIC V1.1b*
READY
>for i=1 to 10:print i:next i
0
0.081


ERROR: C-STACK
READY
>

C-Stack is in external RAM, right? Could I have a bad memory chip or something? I would think this would show up during the memory sizing at reset though.

Frank Kienast