CrazyIcecap wrote:
He is the designer of most of that products
mhh i am not sure. Even the C-One ?
CrazyIcecap wrote:
Peter was writing about the HxC in th a1k.org-forum, and Jens said "If you really want to use that crappy design (no write-support and stone-age-CPLD), at least replace those 74ls05 with 74ls06"
So, now i can answer something:
-> Why i choose a max7000 device ?
Simply because this chip is in PLCC package and that it can be easily solder by any hobbyist.
This is one important criteria of the project : the board must be as simple as possible to be make by most hobbyist.
When i see how many device there are actually, i think we have reached this goal.
Yes, i know that the MAX7000 is an old chip and that it limit the device to a read only support due to his small number of macrocell, but it allowed me to build a device that any hobbyist can reproduce.
And i can add that this CPLD allowed me to make something more powerful than an normal uC:
The bitrate can go up to 1Mbits and can changed in real-time. This allow the full support of IPF and Pasti/STX images. I think that it's the first floppy emulator doing this.
Two years ago, we (Torlus and me)have thought to change this CPLD by a small FPGA (a Spartan or a Cyclone), but unfortunately the pins with a 0.5 mm pitch was a big problem.
Do you really think that there would be near 100 devices today if we used an TQFP100 FPGA? I don't think so. (soldering the small FTDI chip is already a problem for some persons..)
But you know, this is a false problem : Take the VHDL code, synthesis it for a Spartan or a Cyclone (or whatever you want ) chip and you have your "new" floppy emulator
.
That's what Torlus did before having the actual board:
http://www.obsolete-tears.com/hist/vm2006/PICT0023.jpg (2006)
And that's what i did to test the write support (Yes, there are a version with the write support):
https://hxc2001.com/floppy_drive_emulat ... vboard.jpg
And that's what i did for the first stand alone version (2007):
https://hxc2001.com/floppy_drive_emulat ... MG3193.jpg
To be honest, if i could make this emulator with TTL logic chips, I would! Oh my god but I have already did it !
https://hxc2001.com/floppy_drive_emulat ... First2.jpg (the “concept board” of the project
)
I have found the original text from jens about the 74ls06:
Again here Jens have missed the point:
What he wrote is true if you make the design of the host part of the floppy interface, but not the drive part :
74LS05 drive only one resistor : the pull-up present on the host system, even if you plugged 2 or more floppy drive on the bus: Like the HxCFloppyEmulator, disk drives don't have pull-up on theirs outputs...
But 74LS06 shouldn't make problem,so why not.
