5 Mar
2006
5 Mar
'06
12:42 p.m.
made. One other thing that might be of interest :
The 34 pin connector on
the back of the TF20 is not some kind of parallel host interface. It's
exactly what you'd expect a 34 pin connector on a disk controller to be
-- namely a SA400-compatible disk drive bus. The hardware can handle up
If the processor board is left out of the TF-20 you could use the drives
as extra drives on a QX-10. Some more info on the TF-20 and HX-20 Disk basic can be learned from the User manual:
http://electrickery.xs4all.nl/comp/tf20/doc/tf-20_manual.pdf or
http://oldcomputers.dyndns.org/public/pub/rechner/epson/~fjkraan/comp/tf20/….
I haev the user manuals for the HX20 and TF20 on paper. However, the
behaviour of my machine's RS232 port seems to disagree with the manual, I
was wondering if anyone elase had experienced this.
The CP/M like OS in the TF-20 probably doesn't
support the extra drives
I think it's 'real' CPM. There are Digital Reserach copyright messages in
the system image on the disk, there are srings like 'BDOS ERROR', etc.
as the official way to connect more drives is daisy
chaining another
TF-20 to the first one.
Sure. But the controller board _hardware_ certainly supports 4 drives.
Annother odd thing. The cold-start entry in the BIOS seems to initialise
channel B of the 7201 serial chip, which is not normally used (it's
clocked by the same clock that clocks channel A, the TxD and RxD lines
are connected to testpoints on the serial board (TTL level, of course)).
I ought to see if anything ever comes out on those pins...
-tony