ASTRO VG-877 - GCIRC [18 H]: Circle Drawing; CCIRC [12 H]: Circle Clearing

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5
5
INDIVIDUAL DRAWING
COMMAND FORMATS
Execute the drawing commands after having set the sync signals.
With the VG-848 series generator, do not execute drawing commands in combination with pattern
drawing using the main unit. If they are executed together, the patterns may not be drawn on the screen
correctly.
5.1 GCIRC [18H]: Circle drawing /
CCIRC [12H]: Circle clearing
5.1.1 GCIRC [18H]: Circle drawing
Function: This command draws a circle on the graphic plane (1-bit plane).
The center coordinates and radius of the circle are set by the parameters.
Sequence: Type 2
Command:
STX
1 byte
02H
GCIRC, CCIRC
1 byte
18H, 12H
Center X coordinate
2 to 5 bytes
Sign code + “0” to “4095” e.g. 100 “0100”
Sign code: “0” = +, “1” = -
*-2048 (“12048”) to +4096 (“04095”) in numerical
terms
Data delimiter
1 byte
“, “
Center Y coordinate
2 to 5 bytes
Sign code + “0” to “4095” e.g. 100 “0100”
Sign code: “0” = +, “1” = -
*-2048 (“12048”) to +4096 (“04095”) in numerical
terms
Data delimiter
1 byte
“, “
Radius
1 to 4 bytes
“1” to “4095”
ETX
1 byte
03H
Fig. 5-1-1
* A sign code is provided for each of the center coordinates.