Floppy drive for Heathkit 3400 ?

Roger Merchberger zmerch-cctalk at 30below.com
Mon Feb 5 15:14:58 CST 2007

Rumor has it that Steven Canning may have mentioned these words:
>I've been looking into various cheap / easy ways to interface a floppy drive
>to various projects ( i.e. Heathkit ETA-3400 ) for a while. My current path
>is pointing towards using an external USB floppy drive ( $16 USD ) and a
>device from GHI Electronics called a USBwiz ( $60 USD ). This device will
>let you talk to ThumbDrives, SD cards and other USB  " stuff " ( supports
>FAT16 and FAT32 )

Does that USBWiz support FAT12? That would be needed to actually deal with 
floppies; otherwise, you'd have to roll your own FAT12 driver, and that 
might be a touch outside the Heathkit 3400's memory capacity unless you 
have the expansion board (or hacked in more memory on the system).

>   through a very simple interface that a PIC chip has
>enough horsepower  ( computing power ) to drive, so the 6502 in the Heathkit
>should be okay.

If by "6502" you actually meant "6800" ;-) [1], I'd want to remind you that 
they're clocked under 1 Mhz - I think mine has a 500KHz, but my memory's 
fuzzy... A lot of the PICs are clocked at 4+Mhz, IIRC; tho I've never 
tinkered with the PICs, but I've built an AVR board once...

>  I welcome the wisdom of this community as to this pursuit
>before I commit hard earned dollars to said project ( or not ... ). What do
>you guys think ( and yes I already know I'm lazy and should build my own
>hardware ....  ).

I'd have to ask the question: what would be the point of it (being focused 
on the 3400 trainer) - the rascal's only got... uh.... 1K RAM unmodified? 
What could you build to diddle with floppies that would be easier than 
hacking in a UART and sending/receiving over the serial port to the PC? I 
"trained" on these in college, and that was a project that we had to do - 
wire up a UART on each trainer, and send/receive info between Heathkits.

If you're looking for an embedded system, would it not be easier to snag a 
nice cheap CoCo2 w/64K RAM/16+K ROM and hack on it, instead of trying to 
build up such a minimal piece of hardware?

Keep in mind, I *love* my Heathkit 3400... ;-) Just my thoughts...

Roger "Merch" Merchberger

[1] or variant - IIRC, mine has a 6802; it has a built-in timer or 
somesuch... but is 6800 compatible inside and out.

Roger "Merch" Merchberger   | A new truth in advertising slogan
SysAdmin, Iceberg Computers | for MicroSoft: "We're not the oxy...
zmerch at 30below.com          |                         ...in oxymoron!"

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