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There is a new hardware for A8: SIO_FIFO. This device allows data transmission with up to 127kbps speed. Here is the movie with copying disk using this hardware, "US SECTOR COPIER 4" by E.Reuss and AspeQT emulator. SDX, IDE+ loader etc. also working at this baud rate. Form of device is small PCB between POKEY and mainboard. No cables, no solder (if there is a socket for POKEY on the MB). The device is yet in testing phase but will be available soon.

Edited by Simius
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Interesting idea - I guess this device does read/write of it's own accord to SERIN / SEROUT via a local bus?

 

In theory this could be expanded to all manner of other applications, e.g. automated digital sound playack via local buffer.

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SERIN only. Doesn't affect on SEROUT. FIFO is inactive also when baudrate is smaller than 38kbps, then only copies directly the input to the output.

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So it works as read-only insofar as Pokey accesses?

 

How about contention? Does it operate at some multiple of the master clock and do it's reads when it knows that Pokey isn't being accessed?

Edited by Rybags

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FIFO is connected between SIO connector (pin no.3) and POKEY SIO input. Master clock is 18.432MHz. Divisor is choosen (using schedule) depending on the content of AUDF3, so baudrate is the same as POKEY has. Or, when AUDF4 > 0 or AUDF3 > 16 or clock source is other than AUDF3+AUDF4, the state of input is copied to the output (with about 700ns delay).

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OK, way different to what I imagined. So is this just essentially something that allows us to avoid input overrun by buffering more than 1 received and 1 partially received byte at a time?

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It appears to be very fast in the movie. May we see a picture of the device?

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Hello Simius

 

Is this placed underneath POKEY? What if you have a dual POKEY upgrade? Will that fit?

 

Sincerely

 

Mathy

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Hello Simius

 

Is this placed underneath POKEY? What if you have a dual POKEY upgrade? Will that fit?

 

Sincerely

 

Mathy

 

Cool then you can install maybe 2 FIFO's :grin:

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Hello Simius

 

Is this placed underneath POKEY? What if you have a dual POKEY upgrade? Will that fit?

 

Sincerely

 

Mathy

 

Of course. FIFO have to be placed under this one, which handles SIO. The only problem could be the height of set.

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Hello Simius

 

How many millimeters would the FiFo add?

 

Sincerely

 

Mathy

max. 10,3mm (4.5 mm IC socket +1.5mm PCB +4.3mm header)

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Better late than never. :)

Device is working in two modes: FIFO (baudrate greater than border value) and transparent mode (equal or less than border value) and is configurable through $D20C register (write only).

0xxxxxxx - initialization (FIFO cache cleaning)

10aaaaaa - set temporary border value (as AUDF3 content, $00...$3F)

11aaaaaa - set default border value

About 12 pcs. available at the begining of next year. Price: 25USD+5USD shipping.

 

 

 

post-26134-0-64783400-1387579989_thumb.jpg

post-26134-0-24766000-1387580004_thumb.jpg

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simius, what type of apps will benefit from this device, your demo movie by the way is not accessible (says can't find the server at starzaki.eu.org)

Edited by atari8warez

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It's hard to determine. Each can, which uses SIO. I'm using it for example with slightly modified OS, under the ordinary MyDOS.

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It's just a FIFO/buffer to help prevent serial overrun which can be an especial problem at the higher speeds. It doesn't actually play any part in determining what SIO speed is in use though.

 

OK, selling it short - "it's just" is understating - this is giving us something that Pokey could well have done with in the first place.

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