Video driver thoughts

All information relating to the Alpha plus all the WIP threads etc.
User avatar
Icky
Site Admin
Site Admin
Posts: 4013
Joined: Sun Sep 03, 2017 10:57 am
Location: UK

Re: Video driver thoughts

Post by Icky »

exxos wrote: Thu Nov 29, 2018 12:16 am They should be OK I think...

I can only assume really that your chip is faulty as I can't see anything wrong anywhere. Either that or the pinout in the data sheet is wrong..

Will try and build mine up tomorrow and see what happens..
Either I now have added to the BAD collection of BAD DMAs, BAD GALs with a BAD DAC or as you say its something else. If this carries on I am going to get a complex of some sort :)

As you say just need another one of these boards to compare against - will now await the next one to be built.
User avatar
exxos
Site Admin
Site Admin
Posts: 24239
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Video driver thoughts

Post by exxos »

Yeah, bad silicon seems to be the thing of the month...

Will solder the chip and just out power to it and see what voltages I get compared to yours..

But first a quick nap...
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
Icky
Site Admin
Site Admin
Posts: 4013
Joined: Sun Sep 03, 2017 10:57 am
Location: UK

Re: Video driver thoughts

Post by Icky »

exxos wrote: Thu Nov 29, 2018 1:05 am But first a quick nap...
You sleep? You have now shattered the illusion that you never sleep :D. Unless a quick nap is actually a ruse to go and do some more soldering or designing.
User avatar
sandord
Posts: 678
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: Video driver thoughts

Post by sandord »

Icky wrote: Thu Nov 29, 2018 8:34 am
exxos wrote: Thu Nov 29, 2018 1:05 am But first a quick nap...
You sleep? You have now shattered the illusion that you never sleep :D. Unless a quick nap is actually a ruse to go and do some more soldering or designing.
You know that Exxos is actually Chuck Norris in disguise, right? Chuck Norris doesn't need sleep. Just a bit of nap now and then
:D
User avatar
PhilC
Moderator
Moderator
Posts: 6069
Joined: Fri Mar 23, 2018 8:22 pm

Re: Video driver thoughts

Post by PhilC »

:lolbig: :bravo:
If it ain't broke, test it to Destruction.
User avatar
exxos
Site Admin
Site Admin
Posts: 24239
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Video driver thoughts

Post by exxos »

Icky wrote: Thu Nov 29, 2018 8:34 am
exxos wrote: Thu Nov 29, 2018 1:05 am But first a quick nap...
You sleep? You have now shattered the illusion that you never sleep :D. Unless a quick nap is actually a ruse to go and do some more soldering or designing.
Never sleeping sounds about right. Having Thomas the tank engine theme tune in your head on loop for 5 days doesn't help.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
exxos
Site Admin
Site Admin
Posts: 24239
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Video driver thoughts

Post by exxos »

My board is in the cooker.

One other possible thing to consider, is the datasheet says 47uF caps, the Falcon seems to use 220uF, But I used 10uF ceramics. ESR is godlike on ceramics, so shouldn't need as high of value.. but something to keep in mind I guess.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
exxos
Site Admin
Site Admin
Posts: 24239
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Video driver thoughts

Post by exxos »

Will hack job this onto bread board and do some tests...


s.JPG
s.JPG (170.58 KiB) Viewed 3700 times
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
exxos
Site Admin
Site Admin
Posts: 24239
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Video driver thoughts

Post by exxos »

So this has turned into a epic of chaos..

Breadboard on its own, 5V is fine, no shorts... no shorts on the DAC board, plug them bother together it cooks the 5V regulator. So not sure whats going on there.. can only assume something is shorting out when the DAC board is plugged in... so gonna take some working out :roll:
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
exxos
Site Admin
Site Admin
Posts: 24239
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Video driver thoughts

Post by exxos »

So my small PSU has gone wonky again.. so back to my mega psu..
IMG_3600.JPG
IMG_3600.JPG (154.32 KiB) Viewed 3690 times

I tried the RED channel..

R2, R1, R0
000 = 1.68v
001 = 1.89v
010 = 2.10v
011 = 2.30v
100 = 2.51v
101 = 2.71v
110 = 2.92v
111 = 3.12v

So looks like 200mV each step.. which I assume is correct...
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
Post Reply

Return to “ALPHA DEVELOPMENT INFO”