16 Oct
2001
16 Oct
'01
9:59 a.m.
--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote:
Well, as I said 'limited experience'. I
didn't play electronic games (I
still don't) -- I prefered hacking electronics. On the other hand, most
of the games owned by other children at school ended up on my bench to
have battery leads resoldered, LEDs replaced, and so on.
Kids never gave me stuff to fix and return... I got broken stuff and
fixed it if I could. Learned more than I fixed. :-)
In my (limited) experience, most electronic toy/games
from that time
frame contain a mask-programmed microcontroller. Normally a
TMS1000-series device.
Another possibilty is an in-circuit emulator, a box
with a cable
that plugs in place of the mask-programmed IC, and which contains enough
logic (either as TTL or as custom chips, possibly modified versions of
the chip you are emulating) to simulate the chip at full speed, and with
RAM as the program store. Normally there's a serial port to connect to a
host computer to download code, set breakpoints, examine internal
registers and so on. ICE boxes are not cheap, but they are rather fun to
play with if you ever come across one.
I have an ICE for the 68000 - my former employers paid about $20K for it.
It's a big hoot to play with - stores 4096 bus acesses and traces a few
lines if you connect extra probes. Mine was made by Northwest Instruments.
We got it with an original 5-slot PC (5150) to talk to the box with the
RAM, etc., in it. Still have the whole shootin' match, 10Mb add-in drive
and all (we put that in later when we got tired of running off of floppies
and it was <$500).
I've found some interesting hardware bugs with it, like a 68K prototype
with UDS and LDS swapped by mistake - makes byte operations all squirrelly.
-ethan
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