🚀 go-pugleaf

In article <1993Jan20.221146.13845@mixcom.com>
Clint.Laskowski@mixcom.mixcom.com (Clint.Laskowski) writes: 

>Well, I just got my 6811 CPU from Alan Kilian (thanks Alan!).
>I put it in my miniboard, connected the board to my Mac and powered
>it up. Everything seemed to go fine (no smoke!) so I downloaded
>MON (the Mac version). As soon as I downloaded it, all the motor
>LEDs on the miniboard turned "on" (both green and red) and stayed
>on.

This effect (both red and green motor LEDs on with MON) is an
undesirable artifact of the monitor bootstrap routine having turned on
extended addressing.  

You won't be able to control the motor with MON as it is.  I guess I
should fix this.  Alternatively, this effect can be seen as proof that
your motor chips are working, otherwise the LEDs wouldn't light at
all!

>The help info was listed and the system was interactive (ie.
>I could read and write memory locations. I could not turn off the
>motor LEDs. I tried writing $00 and $FF to location $005D. Is this
>normal?

Location $005D is just one humble byte of the 256 bytes in the 6811's
internal RAM.  Writing to it will affect motors IF AND ONLY IF the CPU
happens to be running HEXMON.ASM!  Otherwise you're just trashing a
byte of RAM!!  (I tried to be clear on this in the manual, but people
keep getting confused... am I to blame?)

If you want to control motors directly, write to address $1004, the
location of the 6811 Port B register, to which the motor chips are
connected.  But, because of the MON extended addressing problem, it
probably won't work from MON.  I'll try to fix this soon.

***Please don't confuse the HEXMON "registers" (implemented *only* by
the HEXMON software) with the 6811 register bank (addresses $1000 to
$103F).***


>Does anyone have any .s19 files they could send me which I could
>download to my miniboard to make sure things are working properly?

That's a good idea.

>I think we should work together to write a "Miniboard Test Program"
>which will blink the motor LEDs or something else to let us know
>the boards are working properly.

Alan Kilian has done so; the C source code is archived in
pub/miniboard/hexmon/hxmtest.c.  It requires that HEXMON40 be already
downloaded to the board; it then interacts with HEXMON doing things
like printing sensors values and turning motors on and off.

If someone wants to upload executables of this, that would be nice.

-- 
Fred Martin | fredm@media.mit.edu | (617) 253-7143 | 20 Ames St. Rm. E15-301
Epistemology and Learning Group, MIT Media Lab     | Cambridge, MA 02139 USA