Re: Turbo232 UART Cart HDL

From: Julian Perry <>
Date: Tue, 10 Dec 2013 22:34:00 +1100
Message-ID: <>
Hello GJPAA,

Tuesday, December 10, 2013, 6:40:12 PM, you wrote:

> Hallo Jim,

>> Since this group is probably not interested in aftermarket cart discussions...

> I'm always interested in a technical discussion. 

>> to discuss possible extras that might be of interest in a 6551 interface?

> I don't have any datasheets of the 6551 at hand right now but isn't
> the 16450/16550 able to archive higher speeds?  With a CPLD you can
> now easily generate the Intel signals needed for this IC.

I've seen word of implementations where the 6551 was just overclocked via a
different crystal to higher rates. Since one of the main bottlenecks
in the 8bit world is processor speed, emulating a FIFO buffer (akin to
the 16byte FIFO in the NEC 16550) would be an interesting exercise.

Since the interrupt structure of any programs to USE it would need to
be rewritten (to set thresholds, timeouts/flushes, and multiple-byte
transfers per interrupt cycle, and access the additional registers
necessary) - it would largely be an academic endeavor, unless it had
sufficient utility to establish a standard.

It could be fun, though :)

I always thought that the 6551 ACIA chip was the ONE thing missing from
the C128.


> Met vriendelijke groet / with kind regards,
> Ruud Baltissen

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Received on 2013-12-10 12:00:06

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