Identifying which pins to use on LM1881...

[zedrein]

I am starting to believe that when I first attempted to build a LM1881 circuit for stripping sync from NTSC video, that perhaps I was not using the correct/all the pins.



Here's a diagram of the chip and all of its pins. I used pins 1, 2, 4 [ground] and 8, but I didn't use pin #6 which is labeled as "Rset" According to the description I need to be using that pin. What is it, and why do I need to be using it? Do I need to use any other pins that I am not aware of? I thought that simply plugging in the NTSC video line (with cap) then ground and power and finally composite sync would do the job, but perhaps I was wrong?

Thanks for the help!

EDIT: If you wouldn't mind, I would also like to know the function of pins that aren't used for simple sync-stripping.

[NFG]

You have to connect those two components to pin 6 as well, the rest of them you can safely ignore. 

When hooking those up, I usually just solder them over the top of the chip to connect them to pin 4.  Keeps the whole thing nice and tidy.

[zedrein]

You have to connect those two components to pin 6 as well, the rest of them you can safely ignore. 

When hooking those up, I usually just solder them over the top of the chip to connect them to pin 4.  Keeps the whole thing nice and tidy.

Just to clarify, I will need to connect Composite video and Composite sync to this "Rset" pin? Then from "Rset" I bring one wire to the ground? Would I also need to bring the ground wire from the SNES console that ground pin as well?

Thanks for your patience!

[NFG]

According to the diagram, the only thing you should be connecting to Rset is GROUND, through a capacitor and a resistor.

[zedrein]

According to the diagram, the only thing you should be connecting to Rset is GROUND, through a capacitor and a resistor.

Interesting indeed. May I inquire as to what the "Rset" function is? I feel like such a goomba for not doing this in the very first place.

[NFG]

I never bothered to work out its function, I just hooked it up as instructed and enjoyed the result.  =)

[cgm]

According to the diagram, the only thing you should be connecting to Rset is GROUND, through a capacitor and a resistor.

Interesting indeed. May I inquire as to what the "Rset" function is? I feel like such a goomba for not doing this in the very first place.

Placing different value resisters on the Rset pin changes which scanning frequency the LM1881 operates at.  (From Application Notes http://www.national.com/ds/LM/LM1881.pdf )

[zedrein]

My heavens! I am so excited at the prospects of playing my SNES in glorious RGB that I may need to be sedated. Lawrence [and anyone else for that matter] please tell me what sorta' shock I'm in for so I don't end up collapsing when I first experience gaming visually perfected!