This is a converter from the popular DMX512 protocol to the dead D54 protocol.
A friend working in selling lighting equipments asked me to save his ass, when he sold a new "Mintor" console to a big client as an upgrade to there "Strand EC90" dimmer,
A ready made solutions are available in the market, but he has a problem of he can't wait the shipping & delivery time of 4 weeks, so I did the whole project in 4 days,
The only D54 available data I found was Wikipedia which is based on old Strand doc. I updated wikipedia D54 topic according what I found later after I finished.
This's the wikipedia link after update:
You may notice that +-12 volt path is not regulated, that's because I only want +-5 volt signal swing & LF353 has high supply rejection ratio.
In the forums I found someone asking how to produce negative voltage from AVR (I can't remember where),
I produced -5 volt sync signal using 2 transistors connected to pin PC7,
When PC7 is low => Q2 collector will give -5 volts,
When PC7 is high => Q2 collector will give 0 volts.
This works fine to this project.
There may be a better way, I'd like to know about.
In the schematic U3 is symbolized as a connector it's 8 pin DIL IC SN75176B, but it's not found in my schematic capture software, so I used 8 pin connector instead.
Sooner I'll post another version of the firmware reads DMX without using USART to free it for other purposes.
I wrote the whole thing in AVR assembly which I love it.
Any comment or update or else is welcomed:
Contact me: "portia2220" at "yahoo" dot "com"