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electronic:ttl:start [2021/06/17 11:52]
tony
electronic:ttl:start [2021/06/17 11:56] (current)
tony [TTL from VGA port]
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 Video settings from /​boot/​config.txt:​ Video settings from /​boot/​config.txt:​
  
-# hercules/​ibm5155 crt +|# hercules/​ibm5155 crt| 
-hdmi_ignore_edid=0xa5000080  +|hdmi_ignore_edid=0xa5000080| 
-hdmi_group=2 +|hdmi_group=2| 
-hdmi_mode=87 +|hdmi_mode=87| 
-hdmi_timings=720 1 16 130 16 350 0 16 16 16 0 0 0 50 0 16257000 0+|hdmi_timings=720 1 16 130 16 350 0 16 16 16 0 0 0 50 0 16257000 0|
 ---- ----
 Others say: Others say:
 http://​old.pinouts.ru/​Video/​MDA_pinout.shtml combine RGB signals on the VGA connector together with, say, 330 ohm resistors. Connect H-sync on VGA to H-sync on MDA, same for V-sync, and connect the ground and the MDA intensity line to ground. http://​old.pinouts.ru/​Video/​MDA_pinout.shtml combine RGB signals on the VGA connector together with, say, 330 ohm resistors. Connect H-sync on VGA to H-sync on MDA, same for V-sync, and connect the ground and the MDA intensity line to ground.
  
-VGA outputs are supposed to be .7v (probably higher on some implementations without a proper 75 ohm load though) and MDA is TTL logic level, where >2.4V is considered a high, <.8 is considered a low, and in between is undefined....+VGA outputs are supposed to be 0.7v (probably higher on some implementations without a proper 75 ohm load though) and MDA is TTL logic level, where >2.4V is considered a high, <.8 is considered a low, and in between is undefined....
  
 ===== Hardware description ===== ===== Hardware description =====