Re: Virtual serial drive

[Kevin <kevin@hackaday.com>]

On Wednesday, October 3, 2012 2:31:19 AM UTC-5, Michael J. Mahon wrote:
> Kevin <kevin@hackaday.com> wrote:
> 
> > On Tuesday, October 2, 2012 3:47:25 AM UTC-5, Michael J. Mahon wrote:
> 
> >> Kevin <kevin@hackaday.com> wrote:
> 
> >> 
> 
> >>> I have a almost working model of the host on a AVR + SD card +
> 
> >> 
> 
> >>> breadboard, its all talking, its agreeing on the cheksum, its almost
> 
> >> 
> 
> >>> reading but I only get an hour or two here and there.
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> >> 
> 
> >>> 
> 
> >> 
> 
> >>> but for a sanity check its all looking pretty good, get all the software
> 
> >> 
> 
> >>> going, work out the details, spin a board, and have a virtual serial
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> >> 
> 
> >>> drive backpacked, free of pc tether, on my //c before November
> 
> >> 
> 
> >>> 
> 
> >> 
> 
> >>> as I get things more worked out I will start publishing stuff, right now
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> >> 
> 
> >>> its just a ball o wires and some horrid brute force code.
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> >> 
> 
> >> 
> 
> >> 
> 
> >> You certainly have my interest!
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> >> 
> 
> >> 
> 
> >> 
> 
> >> Sounds like a great way to get a 115kb connection to an SD "hard disk" with
> 
> >> 
> 
> >> a IIc+. ;-)
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> >> 
> 
> >> 
> 
> >> 
> 
> >> -michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon
> 
> > 
> 
> > Well thats a bit more incentive to do it =) few things keep mulling in my
> 
> > head, maybe since you were silly enough to show interest you could chime in.
> 
> 
> 
> ;-)
> 
> 
> 
> > Power: how am I going to get sufficient power to the thing, SD spec calls
> 
> > out for 200mA, and while I know no modern card living in the back of a
> 
> > apple II is going to eat that much, its not going to stop someone from
> 
> > popping in a 12 year old 32 meg card that might. Simple wall wart would
> 
> > solve this but its another thing to plug in. 
> 
> 
> 
> Yes, that would be worth avoiding. 
> 
> 
> 
> Typical current for a modern SD card seems to be in the 40-80ma range, so
> 
> it seems like a shame to be bound by the worst case. 
> 
> 
> 
> >Tapping off the ports on the machine is another option, but then you have
> 
> > this thing snaking all over the place, possibly blocking off something
> 
> > useful, and connectors are not cheap compared to the rest of the board. 
> 
> 
> 
> Yes. Too bad that serial ports don't have power. ;-(.  Maybe a pass-through
> 
> for the joystick port... It would be nice to avoid the extra cable, but
> 
> with a IIc+ I'll need a mini-DIN port adapter anyway. 
> 
> 
> 
> > Clock: its trivial to plop in a RTC, and the one I am eyeballing is like
> 
> > 86 cents a pop, but it adds a layer of complexity just to set the thing
> 
> > to one's local time ... and a battery (or supercap). The thought was I
> 
> > make a utility disk that goes over "normal" serial to the AVR, or just
> 
> > leaving the date/time stamps as zero.
> 
> 
> 
> A utility can always send a non-standard "set clock" packet while using
> 
> standard packets to read back the time. 
> 
> 
> 
> An alternative to the super cap/battery is setting the time at the start of
> 
> each session--better than no time at all. 
> 
> 
> 
> > Multiple images: using ADT you can sneak into a file manager, remove your
> 
> > current disk, plop in a new "virtual.po" file and no one is the wiser. I
> 
> > kind of like that feature. If I make the aforementioned utility disk you
> 
> > could boot to that, set I dunno 5 slots? and when you wanted to switch
> 
> > volumes hit a button on the box. another option is have a device on the
> 
> > side with a LCD screen. That almost instantly doubles the BOM cost.
> 
> > keeping in mind that I currently have the BOM at around 20 bucks not
> 
> > counting PCB and actual card.
> 
> 
> 
> I'm sure some would like multiple images, but I can live very comfortably
> 
> with a 32MB disk image. ;-)
> 
> 
> 
> -michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon

I am going to start a new thread for this as its going to quickly cutter this one which is not my intent