uIEC/SD == AWESOME!
ard at p850ug1.demon.co.uk
Fri Jan 2 13:25:22 CST 2009
> Tony Duell wrote:
> >>> I don;t know how much firmware space you have, but it would be nice if at
> >>> least Amigo and SS/80 could be fitted in together with a jumper/switch to
> >>> select between them. I'd also suggest some kind of configuration
> >>> switch-thingy to select the drive size -- some HP machines moan if the
> >>> drive is not the one they're expecting...
> >> Anything is possible.
> > ... except skiing through a revolving door :-)
> > More seriously, there must be a limit to the code size.
> The unit I am using has 128kB of space, of which I am using 4kB for a
I don't know how code size for that processor compares to similar code on
the 6809 (which always stuck me as being memory-efficient), but I would
think you had enough space for both of the HP protocols.
> bootloader and 51K so far for uIEC DOS. But, a HPIB/GPIB based unit can
> dispense with things like D64 images and such, so I think there may be
> plenty of room. There are provisions for 3 switch inputs, which could
> be used for drive and interface selection. It *might* be possible to
If oyou use one switch to select between SS/80 and Amigo (protocol), that
leaves 2 switches for drive type. Not really enough. And what are you
going to do about sleecting the HPIB primary address (HP units normally
had 3 switches for this, allowing addresses from 0 to 7 only).
> load everything into one firmware image, but I think it'd be best to
> keep the CBM/non-CBM stuff separate.
I would agree. While I have both sorts of machine here, I wouldn't object
to buying/building 2 units, one for each :-).
The other thing to consider wouldf be Tektronix 405x format. I think
those could use HPIB drives. Philip knows more, I think.
> I'm planning on OC outputs.
I beleive that makes it slower, but anyway...
> My idea is to make the ATA (IDE) interface do double duty. As I look at
> the signal table for ATA, I notice a few unused states:
> /CS0 & /CS1 = IEEE CS
> A0 selects data or control lines
> READ selects a read
> WRITE selects a write
> I'll probably use the 75160/75161 ($4.00 for SOIC, $2.80 for DIP for the
Are those still being made? I wouldn't want to design round a chip that's
in short supply.
FWIW, I've had some early HP HPIB units on the bench recently, and HP
used '38s as driers (open collector) and '14s as receivers (schmitt
trigger inputs). Of course using thsoe put the package count up.
> two ICs), though I prefer '245s for the inputs and TPIC6B273s for the
> outputs. (3.40+.82 = 4.42 for the 4 ICs).
> A single '138 should decode what I need from the IDE control signals.
I would guess you'd need latches and buffers between the IDE us and the
More information about the cctalk