Canon A-200 series Service Manual page 106

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• V-RAM
On the color display adaptor board, there are four 16K
x
4 bit D-RAMs. Therefore, 32K bytes
of total storage capacity is available. However, the software can access only 16K bytes.
Actually, used memory capacity is different in each display mode:
*
80
x
25 characters text mode.... .4K bytes
* 40
x
25 characters text mode..... 2K bytes
* 320
x
200 pixels graphics mode..... 16K bytes
*
640
x
200 pixels graphics mode..... 16K bytes
• Clock Generator Circuit
This circuit that is illustrated in the figure below generates a fundamental clock signal for control­
ling the display adaptor itself and a display monitor.
Detailed description for every clock signal is as follows:
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103