On May 15, 2014, at 1:47 PM, Keith Monahan <keithvz at verizon.net> wrote:
Hi all,
I just saw Josh Dersch's message thread right before I came here to talk
about another upgrade I did to my HP16700A.
Oh, that's a neat idea. I need to get one of those one of these days,
though I don't find myself needing a logic analyzer as much as I used
to.
I tested the data rates from an ubuntu PC with an
adaptec card, and I was
getting between 720KB/s - 820KB/s. This is slower, but there's room for
optimization via software upgrade. (and even higher speeds available with
newer uC or FPGA, if there's a future version)
I don't think an FPGA is really necessary to maximize the speed (though a
simple CPLD or one of the really tiny FPGAs they're calling CPLDs these
days might be a boon for sync mode). However, I would love to work with
the guy to bring it to a real microcontroller that has a proper multi-bit
SD controller and external bus interface, like one of the STM32 family,
instead of those dreadful PSoC chips. Maybe I'll drop him a line...
The logic analyzer definitely runs SLOWER with the
SCSI2SD....perhaps in
the neighborhood of 75% of the original speed.
I haven't made up my mind whether I'll keep the modification, try another
device, wait for upgraded software, or maybe just keep it as a spare.
I *will* say that imaging the SD and producing a copy means you can
instantly (as fast as a PC can copy to the microsd card) get back to
factory default. This might be useful, especially with those that like to
tinker!
That is really excellent, especially for those of us with machines that
have built-in SD readers (which are often quite fast).
I've also had discussions with the developer,
Michael McMaster, who is
very responsive.
Good to know. I hope he's interested in working on a next generation!
I think that this device would be perfect for those
older devices where
the speed requirements are much less. The other thread mentions the A3000
-- yes, I think it might be ideal.
Yeah, a logic analyzer has some real bandwidth requirements. An A3000
and a Mac Plus really don't. Hopefully, a new generation will enable
at least 10 MT/s sync mode (not that most SD cards will run that fast,
but at least transferring out of the chip...).
Really cool. So glad someone stepped up to the plate and did this!
The guy who ships has it more right than the guy who spends forever
overoptimizing it and never getting it out the door.
- Dave