Re: Hübner & Worm Hard-Disk 24MB for PET

From: Spiro Trikaliotis <ml-cbmhackers_at_trikaliotis.net>
Date: Tue, 8 Sep 2020 22:15:53 +0200
Message-ID: <20200908201553.GJ1947_at_hermes.local.trikaliotis.net>
Hello,

* On Tue, Sep 08, 2020 at 10:59:55AM -0500 vossi wrote:
> Hi, I added the ROM, Disassembling, manual, flyer, card to my page:
> mos6509.com

thank you for the dump. I am happy to see 6809 assembly again.

All vectors other then the RESET vector point to $FFFF. Thus, it seems,
it does not make use of FIRQ, IRQ, SWI (2,3) or NMI at all! That's
unusual.

At a first glance, I thought you combined the ROMs in a wrong order
(because the RESET vector pointed to $4DF1) until I remembered that the
6809 is big endian, not low endian like the 6502, so the RESET points to
$F14D instead, and it makes sense now. ;)


Do you have any more info?

I see the following bigger chips:

1. MC6809P (the CPU)

2. MC6821P (PIA)

3. An EPROM (?) on top of the MC6821 (2716, if I read it right)? Do you
   know its content?

4. NEC D416C-2 (16K x 1 DRAM) x 8, resultig in 16 KB of RAM.

5. MC68488 (GPIB buffer, that is, the IEEE 488 transceiver)

6. Many additional small ICs (mostly LS-TTL)


Did I miss any important chip, especially some ROM, RAM or I/O?

I think it might be interesting to find out which chip is where in the
memory map.

Regards,
Spiro.

-- 
Spiro R. Trikaliotis
http://spiro.trikaliotis.net/
Received on 2020-09-08 23:00:03

Archive generated by hypermail 2.3.0.