Audio/Video RCA

Philldapill

Here's a quicky. If I'm using pins 0-2 for TV composite output, can I use pin 3 for auidio output, or will the video interfere with this? I've had some PCB's manufactured, and it's an easy fix if it will cause a problem, but I don't want to have to mess with it if it's not needed.

Phil Pilgrim (PhiPi)

If pin 3 is free (i.e. not tied into the video DAC), you can use it for whatever you want.

-Phil

Baggers

Philldapill, don't forget some tv drivers automatically set 4 pins in dira, you may need to change them to just the first three in the group, for the tv driver, just to make absolutely sure no data comes out that pin from the tv cog [noparse]:D[/noparse]

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
http://www.propgfx.co.uk/forum/·home of the PropGFX Lite

·

Philldapill

Both of you guys seem to be "experts" on the subject so I'm glad to get replies from you'll, especially. So, to clarify, using the default TV object, the 4th pin can be used without a problem? On the scope I'm seeing very minor activity on pin 3... I'm thinking this COULD just be an artifact from my long parallel traces acting as stray capacitance, coupling the signal from pin 2... Any thoughts?

Phil Pilgrim (PhiPi)

If pin A3 is still an input, you could well be seeing activity on it coupled from nearby pins. To double check, just add this line to your top-level code:

dir[noparse][[/noparse]3]~~

This sets the pin as an output, which should swamp any cross-coupled noise.

-Phil

Philldapill

Got it. I went ahead and actually TRIED the audio and it's just fine. Thanks alot, guys!

tperkins

Hello Philldapill,

Sorry for the OT post, but the need for it will shortly become clear. I need an email for you to which I can send a Paypal payment and other info to you RE your boards I'd like to order. If your PM's here are full, I can't reply to your generic PM of the 5th.

I look forward to the boards.

Thank you, Tom Perkins