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Re: ssm aio interface
FWIW,
The SSM ASIO Card (Apple Serial I/O Interface, 1981) I have _does_ use the
Motorola 6850 ACIA.
It appears to use different hardware registers than does Apple's Super
Serial Card (SSC), so programs written for the SSC that bypass the higher
level firmware routines would most likely not work without modification.
The SSM ASIO Card, though, is different from the SSM AIO Card. Is the AIO a
serial card, parallel card, or some type of combo?
Hugh...
in article
9a7764a5-50ff-4dd7-8155-8be67fff5042@n33g2000pri.googlegroups.com, David
Wilson at mcs6502@gmail.com wrote on 1/30/09 10:45 PM:
> On Jan 31, 5:36�am, "Michael J. Mahon" <mjma...@aol.com> wrote:
>
>>> it uses a 6550 uart i have found out cables from the asio board will
>>> also work and these were also made by a company called transend
>>
>> That's good news. �I had completely forgotten about the 6550, which I
>> assume has the same bit rate generator as the 6551. �If there are
>> any differences in the control registers or behavior, then it may
>> not work with ADTPro.
>
> According to what I have found, the 6550 was a 1k x4 RAM chip - eBay
> has some for sale as item # 250359789899. Does it perhaps have the
> Motorola 6850? I know many 65xx parts are equivalent to 68xx eg 6820
> and 6520 but I don't remember the 6550 being one.
>
> The 6850 is a 24 pin ACIA with only 3 speeds selectable on chip - /1
> (isosynchronous), /16 and /64 (asynchronous).