Changes between Version 8 and Version 9 of TTLVideoIdeas


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Timestamp:
Nov 15, 2020, 7:32:15 PM (4 years ago)
Author:
Eric Hazen
Comment:

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  • TTLVideoIdeas

    v8 v9  
    11Looking at an all-TTL VGA (640x480) bit-map design.  Inspired by https://eater.net/vga#kits
    22
    3 The decoding isn't terrible.  Rough chip inventory:
     3The decoding isn't terrible.  Rough chip inventory without RAM or latches
    44
    55{{{
    … …  
    2727The pixel cycle time is 39.7ns.  For the video RAM, there is for example the 32Kx8 71256SA12TPG with
    282812ns access/cycle time.  Two chips would be required, providing 8 bits per pixel.
     29
     30New chip inventory:
     31
     32{{{
     33  Counters:       (1) 74AC161
     34                  (1) 74HC4040
     35  Latches:        (3) 74AC574
     36  EEPROM:         (1) AT28C256
     37  VRAM:           (2) 71256SAxx
     38}}}
     39
     40Much better.  Definitely worth a prototype build.