Can´t get work TV out at basepin P10..Why ??

BTX

Hi all
I´m stuck with this stupid problem, I´m connecting the 1.1K, 560 Ohm, and the 270 Ohm R´s, at the pins P10, P11, P12 for video out, but I can´t get work in those pins.
What is happening ?? am I missing something ? or it´s a bug of the driver.
I´m using "TV Text Demo v1.0" from Chip Gracey.

It works fine in pins, (0,1,2), (1,2,3),.... (12,13,14), but wont work in (8,9,10), (9,10,11), (10,11,12).

Thanks in advance.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Regards.

Alberto.

Mike Green

The TV pin groups must start at a multiple of 4, so you can have P0-3, P4-7, P8-11, P12-15, P16-19, P20-23, P24-27, and theoretically P28-31.

BTX

Oh...Thanks so much Mike !!
Every day I learn something new..I´ve never listen about that limitation, now I´m in a big problem my PCB was done with pins 10, 11, 12.
I suposse there is no way to modify the driver easily, I tried with "tv_pins := (basepin & $38) << 1 | (basepin & 2 == 2) & %0101"
but no luck.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Regards.

Alberto.

Paul Baker

No, the Video Generator is hardwired to work on a modulo 4 pin out, so theres no way to modify a driver that uses the VG to work on P10-P12.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Paul Baker

Philldapill

Ouch. Epic burn by Paul Baker.

Paul Baker

It wasn't a burn, I'm very familiar with the VG (I wrote the·data sheet covering it's operation) and was just relaying the info.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Paul Baker

Philldapill

No, I know you didn't mean to, Paul. I just found it funny how you shot down such a complicated topic as the VG and why the pins must be a multiple of 4... all in one line. I've had a question or two about this subject, myself. However, I'm sure Alberto has alot more experience with the issue than I do and doesn't need a lengthy explaination.

Phil Pilgrim (PhiPi)

BTX,

'Bummer about the board layout. That's a rough pin combination, to be sure. You might get something to work if you're willing to forgo color output. It would involve using pins 8..15 and an 8-bit (VGA) video mode, with all but pins 10..12 masked out. You'd have to modify TV.spin for the unusual arrangement, though, just to generate the proper sync, among other things. In your shoes, I'd redo the board layout. In the end, you won't regret it.

-Phil

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
'Just a few PropSTICK Kit bare PCBs left!

BTX

Thank you all guys for the answers !!.
Phill you´re right, I´ll redo my PCB... sometimes we´ve to lose, simple solution this time, in the future, I will try a prototype before.

Comments:
I´m testing it in pins (1,2,3), (5,6,7), and it works in a B/W TV Such a strange !.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Regards.

Alberto.

Envio editado por (BTX) : 12/22/2008 9:57:31 AM GMT

Phil Pilgrim (PhiPi)

Alberto,

To save yourself as much grief as possible, lay out your board to use one of the following combinations: 0-2, 4-6, 8-10, 12-14, 16-18, 20-22, or 24-26. If you need broadband video with FM sound, you will need to add the fourth pin in each sequence (e.g. 12-14 becomes 12-15).

-Phil

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
'Just a few PropSTICK Kit bare PCBs left!

BTX

Thank you so much Phil !!

Yes, now I know that, before, I thought that any pin was possible for TV out.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Regards.

Alberto.