This shows you the differences between two versions of the page.
electronic:ttl:start [2021/06/17 11:52] tony |
electronic:ttl:start [2021/06/17 11:56] (current) tony [TTL from VGA port] |
||
---|---|---|---|
Line 20: | Line 20: | ||
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 ===== |