[Coco] Disto SC add-ons

[John Eric]

Roger, Tony did an article on this board for Rainbow, I think it was called "Increasing Character Display" and if I'm not mistaken, it's in "A Full Turn of The Screw" which I've found on the maltedmedia ftp. It gives the CoCo's addresses for the register map - i think it was mapped in such a way that you write the address to the chip via a port, then you read or wrote the data to that location, and so on. It worked with basic and OS-9 - the original C-DOS had the D80 ON/OFF commands. I think the one you have supported smooth scrolling (by pixel rather than character). It should be simple enough, with the turn of the screw article, to write a disk basic driver - intercept the RAM Hook for video and route it to the driver. -J.eric




________________________________
From: Roger Taylor <operator at coco3.com>
To: cocolist for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Tuesday, December 30, 2008 2:02:46 PM
Subject: [Coco] Disto SC add-ons

Does anyone know how in the heck the addon with the video chip is supposed to output video or how it works?  The board also has a clock chip which seems to be running even though the board is old.. you can PEEK from BASIC and see the clock registers changing.  I do have the register specs on the clock.  The video chip is a CRT9128. There's an 11mhz crystal, HM6116LP-2 chip, 13x2 header, and 2x2 header.  I see no other ID marks on the board other than the word "Disto" and two color stickers on the back labeled "M" and "T".

I see nothing in the Disto SC docs explaining the details of this board, just a mention that it's one of the add-ons.
-- Roger Taylor

http://www.wordofthedayonline.com


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