GUBBINS@TOPS20.RADC.AF.MIL (Gern) (05/22/89)
The following is the brief DOC file for the CCI Imagewise Frame Grabber
program for the Z-100. I see some of you have FTPed it already.
SHOWPIW.DOC Gern
11-AUG-88
CCI ImageWise Low Cost Frame Grabber Display Program For Zenith Z-100
SHOWPIW [filename] [/X]
Display Mode Switches:
512x480 Default (Interlaced, 16 Levels Dithered)
/R = 512x225 Regular (Non-Interlaced, 8 Levels)
/S = 256x244 Small (Interlaced, 8 Levels)
/F = 640x480 Full Screen (Interlaced, 16 Levels Dithered)
PIW File Resolution:
256x244 NTSC
6-bit (64 Levels) Grey Scale
This program for the Zenith Z-100 displays PIW Picture Data Files from
the Circuit Cellar Inc. Imagewise Low Cost Frame Grabber (Digitizer).
Further information on the Imagewise can be found in BYTE Magazine issues
MAY-87 to AUG-87.
The desired output is contained in the grey level of the video color (each
of the 8 colors of the Z-100 is a different grey level). To properly
see the picture use the Z-100 composite video output to a monochrome
video monitor (ZVM-135 composite input mode works as well). If the
RGB video output is displayed, the picture's 'false color' will show.
This program can display the PIW data in different modes, by sizing the
256x244 pels of data to the Z-100 screen by different methods. By using
two Z-100 pixels in the x and y-axis for each PIW pel, dithering is used
to fake more displayed levels of grey scale using the Z-100's 8 color/grey
levels out of the 64 grey levels of data.
The PIW Data Format:
Bit Number Bit
7 6 5 4 3 2 1 0 Definition
0 0 x x x x x x Video Data Byte
0 1 0 0 0 0 0 0 Start Of Video Field
0 1 0 0 0 0 0 1 Start Of Video Line
0 1 0 0 0 0 1 0 End Of Video Field Data
0 1 1 x x x x x Reserved
1 0 0 0 x x x x Repeat Previous Byte X Times (0 = 16 Reps)
1 0 0 1 x x x x Repeat Previous Byte 16X Times (0 = 256 Reps)
1 1 x x x x x x Reserved
HOGWARE makes a very nice program called ZIP for the Z-100 to use the
Imagewise Digitizer.
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