VideoNuLA boards

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RobC
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Re: VideoNuLA boards

Post by RobC » Thu Sep 05, 2019 8:48 pm

dominicbeesley wrote:
Thu Sep 05, 2019 10:55 am
I've played around with the tools in Altera but not really worked out a regime for optimisation beyond guess work and trial and error...
Pretty much trial and error. When I've hit a limit in the past, I've just used educated guess work to figure out a way round it. More often than not, it's come down to repeatedly thinking up new ways of implementing something until it fits :oops:

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Re: VideoNuLA boards

Post by dominicbeesley » Mon Sep 09, 2019 5:41 pm

Good to know I'm not alone!

I've now hit the limit so I need to start optimising...this could be fun

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Re: VideoNuLA boards

Post by rayfenwick » Mon Sep 16, 2019 11:53 pm

Am I too late? :shock:

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Re: VideoNuLA boards

Post by jgharston » Tue Sep 17, 2019 12:16 am

dominicbeesley wrote:
Wed Sep 04, 2019 6:24 pm
It's turned out to be not such a problem in the end I just reset every frame and put up with the occasional glitch - I must track down where these rogue vsyncs are coming from!
In the updated *LDPIC that's what I did, wait for VSync (OSBYTE 19) then do a nULA reset. Very occasionally I would notice a very brief flicker between the reset and then the new palette being programmed. There's only a handful of instructions out of the OSBYTE 19 code back to the caller*, so there's only a couple of dozen or so CPU cycles between waiting and being able to write.

*To save one byte OSBYTE 19 falls through into OSBYTE 160, so once a Sync has happened, there's
LDY &0301,X:LDA &0300,X:TAX:RTS:ROR A:PLP:ROL A:PLA:CLV:RTS

before you get back to the caller, 36 cycles if I've counted right.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.32
(C) Copyright J.G.Harston 1989,2005-2020
>_

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Vyper68
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Re: VideoNuLA boards

Post by Vyper68 » Tue Sep 17, 2019 8:35 am

Got my NuLa last week and it's a great upgrade to my Beeb. When I get a Master i'll be coming back for another :D
Save time… see it my way.

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Re: VideoNuLA boards

Post by dominicbeesley » Tue Sep 17, 2019 11:06 am

jgharston wrote:
Tue Sep 17, 2019 12:16 am
dominicbeesley wrote:
Wed Sep 04, 2019 6:24 pm
It's turned out to be not such a problem in the end I just reset every frame and put up with the occasional glitch - I must track down where these rogue vsyncs are coming from!
In the updated *LDPIC that's what I did, wait for VSync (OSBYTE 19) then do a nULA reset. Very occasionally I would notice a very brief flicker between the reset and then the new palette being programmed. There's only a handful of instructions out of the OSBYTE 19 code back to the caller*, so there's only a couple of dozen or so CPU cycles between waiting and being able to write.

*To save one byte OSBYTE 19 falls through into OSBYTE 160, so once a Sync has happened, there's
LDY &0301,X:LDA &0300,X:TAX:RTS:ROR A:PLP:ROL A:PLA:CLV:RTS

before you get back to the caller, 36 cycles if I've counted right.
Plus any interrupts?

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Re: VideoNuLA boards

Post by jgharston » Tue Sep 17, 2019 11:36 am

dominicbeesley wrote:
Tue Sep 17, 2019 11:06 am
jgharston wrote:
Tue Sep 17, 2019 12:16 am
*To save one byte OSBYTE 19 falls through into OSBYTE 160, so once a Sync has happened, there's
LDY &0301,X:LDA &0300,X:TAX:RTS:ROR A:PLP:ROL A:PLA:CLV:RTS
before you get back to the caller, 36 cycles if I've counted right.
Plus any interrupts?
Interupts are disabled until the PLP, so
LDY &0301,X:LDA &0300,X:TAX:RTS:ROR A:PLP:ROL A:PLA:CLV:RTS
22 cycles plus 14 cyles and any interupts. That could well be the source of the flicker, if something manages to get in during those four instructions.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.32
(C) Copyright J.G.Harston 1989,2005-2020
>_

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Re: VideoNuLA boards

Post by 1anking » Thu Oct 10, 2019 10:01 am

Hi Rob,

Do you still have VideoNula boards available?
Please could you send me a PM if you have a unit for sale - just got my Beeb up and running and wanting to replace my Video ULA which has the old heatsink on an Issue 3 board.
Thanks
Ian

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Re: VideoNuLA boards

Post by RobC » Sun Oct 13, 2019 9:32 pm

1anking wrote:
Thu Oct 10, 2019 10:01 am
Do you still have VideoNula boards available?
PM sent. Unfortunately, due to work and family commitments, I don't have the time to make as many boards as I used to or do Beeb stuff in general :( .

However, I have a few ready at the moment and can usually find time to make one or two boards now and again if people want them.

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Re: VideoNuLA boards

Post by simply_graham » Mon Oct 28, 2019 12:33 pm

Hi Rob

I'm not in any great rush But I'd like one in the future please. I've not enough posts to allow me to PM you. but did see your reply a few weeks back, hence no rush

BR
Graham

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Re: VideoNuLA boards

Post by RobC » Tue Oct 29, 2019 6:03 pm

Hi Graham,

Thanks for the interest. Unfortunately, I only have one here at the moment and that's reserved for someone who wants it fitting to a Master.

I'm a bit under the weather at the moment but I should be able to make one up on the weekend. I'll let you know as soon as I have one available.

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Re: VideoNuLA boards

Post by stevebubs » Tue Nov 05, 2019 11:53 pm

Hi,

If you're doing a batch when you feel better, I'd quite like one for my Master, too?

Steve

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Re: VideoNuLA boards

Post by RobC » Mon Nov 11, 2019 12:22 pm

simply_graham wrote:
Mon Oct 28, 2019 12:33 pm
I'm not in any great rush But I'd like one in the future please.
stevebubs wrote:
Tue Nov 05, 2019 11:53 pm
If you're doing a batch when you feel better, I'd quite like one for my Master, too?
I have a couple made up now if either of you are still interested.

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Re: VideoNuLA boards

Post by stevebubs » Mon Nov 11, 2019 12:53 pm

Definitely. Will PM you now

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Re: VideoNuLA boards

Post by jubber » Wed Nov 13, 2019 7:42 pm

I was going to grab a link to the ones I saw on ebay a while ago so that my clueless relatives can get me something I actually want this year - but it's not there anymore. If you decide to repost on ebay, please give me a shout, or if there's a simple way to order from you directly, the details would be much appreciated.

It's sort of a yearly rigmarole I have to go through. My sisters and mum don't know what I want, so I give them a list and then look vaguely surprised on the 25th :-)

Cheers,

Robin

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Re: VideoNuLA boards

Post by RobC » Thu Nov 14, 2019 12:43 pm

Hi Robin,

Thanks for the interest. The cheapest way to get hold of one is to contact me directly as it saves on eBay fees (and GSP if you're not in the UK). I'll PM you my contact details.

I have one spare board in stock at the moment but will be making a few more soon.

Best wishes,

Rob

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Re: VideoNuLA boards

Post by simply_graham » Wed Nov 20, 2019 10:22 pm

Hi Rob
Yes I am still interested but it appears I can't PM you.

If you have an online store would there be any contact details under that ?
I have searched nothing found in Flee Pay

(And I'll sign in a little more, just been rebuilding a number of PSU on failed Beeb's and busy with life)

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Re: VideoNuLA boards

Post by sydney » Wed Nov 20, 2019 10:43 pm

simply_graham wrote:
Wed Nov 20, 2019 10:22 pm
Hi Rob
Yes I am still interested but it appears I can't PM you.

If you have an online store would there be any contact details under that ?
I have searched nothing found in Flee Pay

(And I'll sign in a little more, just been rebuilding a number of PSU on failed Beeb's and busy with life)
I've just enabled pm's for you.

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Re: VideoNuLA boards

Post by RobC » Thu Nov 21, 2019 12:35 pm

Thanks Sydney.
simply_graham wrote:
Wed Nov 20, 2019 10:22 pm
Yes I am still interested but it appears I can't PM you.

If you have an online store would there be any contact details under that ?
I have searched nothing found in Flee Pay
I've PM'd you my e-mail address. No online store I'm afraid and I've not put many on eBay recently as I'm only making them in small batches as time allows.

Best wishes,

Rob

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Re: VideoNuLA boards

Post by Chuckie » Mon Nov 25, 2019 10:52 am

I am interested in a videonula board cant seem to pb please contact me

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Re: VideoNuLA boards

Post by RobC » Mon Nov 25, 2019 9:06 pm

Chuckie wrote:
Mon Nov 25, 2019 10:52 am
I am interested in a videonula board cant seem to pb please contact me
PM sent.

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Wanted: VideoNULA

Post by DigitalDunc » Sat Dec 28, 2019 7:47 pm

Hey! I'm after a VideoNULA, but they don't appear available at the moment. Does anyone have one I might buy?

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Re: Wanted: VideoNULA

Post by danielj » Sat Dec 28, 2019 10:18 pm

DigitalDunc wrote:
Sat Dec 28, 2019 7:47 pm
Hey! I'm after a VideoNULA, but they don't appear available at the moment. Does anyone have one I might buy?
Merged this with the appropriate topic :)

d.

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Re: Wanted: VideoNULA

Post by RobC » Sat Dec 28, 2019 10:23 pm

DigitalDunc wrote:
Sat Dec 28, 2019 7:47 pm
Hey! I'm after a VideoNULA, but they don't appear available at the moment. Does anyone have one I might buy?
I don't have any spares made up at the moment but am off work for a couple of days next week so can make one for you.

They are still £50 +P&P (£2.50 in the UK). PM me or reply here if you're still interested.

Cheers,

Rob

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Re: VideoNuLA boards

Post by banedon88 » Wed Jan 01, 2020 6:11 pm

Hi Rob

I've only just come across the VideoNULA and it sounds very interesting.
Would you be ok making one for me as well if you have the parts & time?

[edit] obviously I'll pay (forgot to mention that part! :mrgreen: )

Kind regards
Mike

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Re: VideoNuLA boards

Post by Remklep » Wed Jan 01, 2020 7:02 pm

I‘m interested in a board too, thnx.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: VideoNuLA boards

Post by RobC » Wed Jan 01, 2020 8:58 pm

Thanks both for the interest.

I have the parts here so I'll make a couple more boards up in the next few days and will get back to you.

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Re: VideoNuLA boards

Post by Remklep » Wed Jan 01, 2020 9:00 pm

RobC wrote:
Wed Jan 01, 2020 8:58 pm
Thanks both for the interest.

I have the parts here so I'll make a couple more boards up in the next few days and will get back to you.
Thank you kindly Sir.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: VideoNuLA boards

Post by Remklep » Wed Jan 01, 2020 9:01 pm

If you want, you can also send me the kit, I can do the soldering myself.
Unless it's smd, I don't enjoy soldering smd.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: VideoNuLA boards

Post by RobC » Wed Jan 01, 2020 9:18 pm

Remklep wrote:
Wed Jan 01, 2020 9:01 pm
If you want, you can also send me the kit, I can do the soldering myself.
Unless it's smd, I don't enjoy soldering smd.
It's pretty much all SMD (and the CPLD is 0.5mm pitch...). I should be able to get them done over the next couple of evenings though.

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