28 lines
965 B
Plaintext
28 lines
965 B
Plaintext
max 256k for upd7220
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mak 2mb for upd72020
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800x600 is *barely* possible with
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32k sram is the largest available in dip with the speed neccesary
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blanking area *may* be possible on chip. if not the chip produces the neccesary signals. some external logic
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800x600 requires dividing pixel clk by 5 to get 8mhz signal clk
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this all assumes 4 bit using memory pages
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128k + 32k = 160k
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5x 32k sram - a lot of ram
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160k is enough for 4 bit color at 640x480
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160k is enough for 2 bit color at 800x600
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simplest to implement, both are standard vga resolutions
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32k + 8k = 40k
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1x 32k sram + 1x 8k sram - two diff chips
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40k is enough for 1 bit color at 640x480
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40k is enough for 4 bit color at 320x240 or 320x200
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needs linedoubling for 320x240
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needs linedoubling and blank area for 320x200
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32k
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1x 32k sram - simplest, 1 chip
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32k is enough for 1 bit color at 640x400
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32k is enough for 4 bit color at 320x200
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needs blank area for 640x400
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needs linedoubling and blank area for 320x200
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