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Old 1st Jul 2015, 8:23 pm   #14
SiriusHardware
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Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,485
Default Re: The Sinclair / Science of Cambridge MK14

Quote:
Originally Posted by TonyDuell View Post
If you're not careful, though, you end up with a VDU which is nothing like SOC designed.
Not in this case. You use the MK14 VDU hardware exactly as designed and the MK14 hardware exactly as designed: You just put a dual-port RAM between them so that the VDU reads continually from that, leaving the MK14 with all its RAM available and running at full speed, writing data into the other port of the dual port RAM every now and then.

Quote:
Originally Posted by TonyDuell View Post
As for the character generator, it can't be hard to work out a suitable bit pattern for a character font and blow it into some kind of PROM or EPROM.
Not hard, but unnecessary. You could find the data sheet for a HD44780 LCD display driver IC and pinch the already designed character set from that: I was assuming the aim was to make an exact clone of the MK14 VDU, in which case it would need to have the same character set with the same codes to access them (it only has 64 characters, no lower case, and many of the miscellaneous ASCII characters are missing).
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