Re: Turbo232 UART Cart HDL

From: Jim Brain <brain_at_jbrain.com>
Date: Fri, 13 Dec 2013 23:03:55 -0600
Message-ID: <52ABE6BB.60807@jbrain.com>
On 12/13/2013 3:02 PM, Mike Naberezny wrote:
> Hi Spiro,
>
> On 12/13/13, 11:22 AM, Spiro Trikaliotis wrote:
>> * On Wed, Dec 11, 2013 at 05:14:31PM -0800 Mike Naberezny wrote:
>>
>>> Novaterm and DesTerm 128 also support the HART cartridge from
>>> Hatronics.  This was an 8250-based design.  It should be possible to
>>> install a 16550 in a HART cartridge but I haven't tried it.
>>
>> Does anyone have more information on that cartridge?
>
> I have a HART cartridge.  I added a page for it:
> http://mikenaberezny.com/hardware/c64-128/hatronics-hart-rs-232/
>
> Regards,
> Mike
>
Oh... MY GOODNESS!  What an interface!

It grabs 8 bytes at $de18 for read, and 8 bytes at $df18 for write. I 
can somewhat understand the read/write thing (sent IO1 to !RD and IO2 to 
!WR), with the ttl logic filtering the adress lines, but WHY?  8250 has 
complementary RD and WR signals, so you can easily integrate with 
65/68XX logic by tying RD to !WR, tying !RD high, and WR low, and 
pushing PHI2 through CS0 while using CS1 and !CS2 as your enable 
signals.  So much hurt there.

Jim

-- 
Jim Brain
brain@jbrain.com
www.jbrain.com


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Received on 2013-12-14 06:00:04

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