VideoNuLA boards

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1024MAK
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Re: VideoNuLA boards

Post by 1024MAK » Thu Oct 05, 2017 5:02 pm

danielj wrote:Given the price for a 28pin one of these, I think you're best off just getting some more NuLAs.... http://www.ebay.co.uk/itm/172803690952

d.
I prefer Farnell's price :wink:

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MartinB
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Re: VideoNuLA boards

Post by MartinB » Thu Oct 05, 2017 5:25 pm

If I'm reading Toby's page correctly, you can get 28-pin headers a lot cheaper - £0.60 for one + VAT + £3.95 postage as far as I can see?

https://www.toby.co.uk/content/catalogu ... =606-xx-R1

Toby DIL headers.JPG

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danielj
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Re: VideoNuLA boards

Post by danielj » Thu Oct 05, 2017 5:30 pm

Phew!

Clearly searching for the wrong thing :D

d.

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Re: VideoNuLA boards

Post by RobC » Thu Oct 05, 2017 5:48 pm

1024MAK wrote:I prefer Farnell's price :wink:
I've found out where I bought mine from: Unicorn Electronics

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Re: VideoNuLA boards

Post by RobC » Mon Oct 23, 2017 8:16 am

I've made another batch of boards in preparation for the RISC OS London Show.

If you're coming to the show, you'll be able to see VideoNuLA in action and have a play with it. If you want to purchase one (or more!), I'll have units available to buy on the day. I'm also giving a talk on its development for those who want to find out more.

For those who want one but aren't coming to the show, just PM me or express your interest in this thread.

Price is £50 per unit (plus £2.50 P&P for UK delivery). I can get postage quotes for those living overseas.

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mattyj
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Re: VideoNuLA boards

Post by mattyj » Sun Nov 26, 2017 12:46 am

Hi Rob
Could I purchase one of these boards please?
Kind regards
Matt

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Re: VideoNuLA boards

Post by jgharston » Thu Dec 21, 2017 9:54 am

Writing to &FE23 toggles between writing index*16+red and writing green*16+blue. Is there some way of resetting the toggle to a known state so that you know that your next write to &FE23 is going to be, eg, the index*16+red ?

Edit: the manual says writing &4x to the control register reset nULA to its default state, then lists these default states, but the &FE23 toggle is not listed in that list.

(I'm getting weird deja vu, I'm sure I've asked this before....)

ta.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: VideoNuLA boards

Post by RobC » Thu Dec 21, 2017 11:18 am

jgharston wrote:Edit: the manual says writing &4x to the control register reset nULA to its default state, then lists these default states, but the &FE23 toggle is not listed in that list.
The reset command (?&FE22=&4x or *VNRESET) also resets the toggle state so that the next poke to &FE23 sets the index and red component. I'll add this to the manual.

Also, following Lardo Boffin's "SpectROM" suggestion, I've recently revised the VHDL to make a little extra room in the CPLD and have added another attribute mode which can replicate the Spectrum's display (it's actually closer to the Thomson TO7 as attributes affect an 8x1 pixel block).

I'm currently working on a Spectrum emulator for the Pi copro to go alongside it. It's in its early stages so I'm not sure how useful it'll be but, if it does turn out to be of use, I'll upgrade existing boards for free.

Also, if anyone wants a board, I still have a few bare PCBs that I can make up over the holidays. There are still some listed on eBay but they are more expensive to cover the eBay fees...

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Re: VideoNuLA boards

Post by jgharston » Thu Dec 21, 2017 7:58 pm

RobC wrote:
jgharston wrote:Edit: the manual says writing &4x to the control register reset nULA to its default state, then lists these default states, but the &FE23 toggle is not listed in that list.
The reset command (?&FE22=&4x or *VNRESET) also resets the toggle state so that the next poke to &FE23 sets the index and red component. I'll add this to the manual.
Thanks. A suggestion: put a "parameter" column in the auxilary register summary table on on page 28 as an aide memoir, something like:
code | function | parameter
1 | set palette mode | physical/logical mapping
2 | set horizontal | offset offset
3 | set left blanking size | size
4 | reset | none
etc.

It turns out the reason I tearing my hair out was that I was programming the physical pallette using logical mapping. (I've programmed colours 0-3, why is the blue still blue???? Oh, that's physical colour 4....)
RobC wrote:Also, if anyone wants a board, I still have a few bare PCBs that I can make up over the holidays. There are still some listed on eBay but they are more expensive to cover the eBay fees...
Yes please! I've currently been testing code with the beta B-Em - which fights with AVG over control of my machine.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: VideoNuLA boards

Post by RobC » Thu Dec 21, 2017 8:12 pm

jgharston wrote:Thanks. A suggestion: put a "parameter" column in the auxilary register summary table on on page 28 as an aide memoir, something like:
code | function | parameter
1 | set palette mode | physical/logical mapping
2 | set horizontal | offset offset
3 | set left blanking size | size
4 | reset | none
etc.
Will do. I should have some time to revise the manual and support pack over Christmas alongside the Spectrum emulator work...
jgharston wrote:
RobC wrote:Also, if anyone wants a board, I still have a few bare PCBs that I can make up over the holidays. There are still some listed on eBay but they are more expensive to cover the eBay fees...
Yes please! I've currently been testing code with the beta B-Em - which fights with AVG over control of my machine.
Great - I'll PM you the payment/PayPal details (cost is £52.50 including UK P&P).

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Re: VideoNuLA boards

Post by jgharston » Sun Dec 24, 2017 3:19 am

I missed getting a nULA at ABUG, so have been experimenting with the implementation in the current beta of B-Em.

I decided to update my screen saving/loading tools to add support for 12-bit palettes. I started with my *ScrSave/*ScrLoad commands, but they store the palette in the load/exec addresses, and you need 192 bits to store the 12-bit pallet, so would have to look at including the palette data in the data stream itself.

So, I went back to the Acorn User LDPIC/SVPIC which do store the palette in the data stream, and have added support for the 12-bit nULA palette in a manner where old *LDPIC will still load new files with a 12-bit palette, and new *LDPIC will still load old files without a 12-bit palette. The palette is simply added at the end of the compressed data as 48 x 4-bit entries.

NULATEST.SSD is a couple of screen files with 12-bit palette and one with no 12-bit palette. The actual colours are a bit bleah as I just twiddled to get something as a demo.

I've been attached to ScrLoad/ScrSave as I wrote them, but LDPIC/SVPIC crunch about 10% better, and it's been easier to add the 12-bit palette, so I'm tempted to rebuild my pictures disks using LDPIC/SVPIC.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: VideoNuLA boards

Post by jgharston » Tue Jan 16, 2018 2:14 am

The post on Spectrum attirbute mode reminds me of a discussion I was having with RobC earlier.

The VideoNuLA support ROM allows to select the extended display features with MODE/VDU 22. It currently uses MODEs &60-&68 as a straight sequence of numbers. I mentioned that it would match the native MODE numbering sequence to have the mode numbers logically numbers based the mode number they were based on, giving the sequence:

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MODE text clrs mem  MODE text clrs mem           MODE text clrs mem
 0  80x32   2  20K  &60 80x32   5  20K MODE 0+4  &68  80x32  9  20K MODE 0+8
 1  40x32   4  20K  &61 40x32  13  20K MODE 1+4 
 2  20x32  16  20K
 3  80x25   2  16K  &62 80x25   5  16K MODE 3+4  &6B  80x25  9  16K MODE 3+8
 4  40x32   2  10K  &63 40x32   5  10K MODE 4+4  &6C  40x32  9  10K MODE 4+8
 5  20x32   4  10K
 6  40x25   2   8K  &64 40x25   5   8K MODE 6+4  &6E  40x25  9   8K MODE 6+8
 7  40x25   8   1K
That is, MODE &60+n is MODE n with 4 extra colours, MODE &68+n is MODE n with 8 extra colours, in the same way that MODE 8+n is MODE n with twice the colours.

MODE &60 and MODE &61 are the same as the straight &60-&68 numbering.

So, the question is, has anybody used the VideoNuLA Support ROM to produce code that they have released using MODE or VDU 22 with mode numbers other than &60 and &61? Of the demos I've seen they all seem to be done with direct hardware manipulation, without using the VideoNuLA support ROM, and the code I've seen using the Support ROM have only used MODE &60, I think the multi-colour text terminal (can't remember the name at the mo). I think the shuffling would also allow the Spectrum screen mode to have a number that slots in logically as well.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: VideoNuLA boards

Post by jgharston » Tue Jan 16, 2018 2:18 am

Has anybody used the nULA board in a Master Compact? I have a floppy drive mounted internally in my Compact, before I look for my soldering iron, is the board likely to fit?
Image

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$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: VideoNuLA boards

Post by RobC » Tue Jan 16, 2018 8:42 am

jgharston wrote:Has anybody used the nULA board in a Master Compact?
I have one in my Compact and it fits without any problems as long as you don't have an Econet module fitted. However, mine doesn't have a floppy inside the case so I don't know if it'll fit in yours.

I keep meaning to try putting VideoNuLA at the end of a 28-way ribbon cable - I've made up the cable but I keep getting distracted by other projects!

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Re: VideoNuLA boards

Post by rogerjowett » Wed Jun 06, 2018 11:00 am

does it have vertical and horizontal scrolling
how big is the palette what are the video modes supported please?

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Re: VideoNuLA boards

Post by RobC » Wed Jun 06, 2018 12:01 pm

rogerjowett wrote:
Wed Jun 06, 2018 11:00 am
does it have vertical and horizontal scrolling
It adds single pixel horizontal scrolling in the highest resolution modes 0 & 3. This means you can do 1/2 pixel scrolling in modes 1 & 4 and 1/4 pixel scrolling in modes 2 & 5 (as used in my Shadow of the Beast demo).

It doesn't add any vertical scrolling features as single pixel vertical scrolling can already be done using the standard hardware and the vertical rupture technique.
rogerjowett wrote:
Wed Jun 06, 2018 11:00 am
how big is the palette what are the video modes supported please?
The extended palette is 4096 colours (4-bits for red, green and blue) and can be used to redefine colours in all existing modes including teletext/mode 7. It also allows you to use 16 different solid colours (out of the 4096) in mode 2 and there are additional "attribute" modes that allow more colours on screen at the expense of horizontal pixel and/or colour resolution. For example, there's an 8 colour, 80 column text mode and a mode that can mimic the ZX Spectrum's display.

Full details are in the manual which can be downloaded from here but do feel free to ask me any further questions.

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Re: VideoNuLA boards

Post by jmc » Tue Sep 18, 2018 6:23 am

Hi Rob,

Great work on the VideoNuLA! Boy oh boy, how we all wished we had something like this back in the day! Incredible.

I have two questions about ordering (can't PM yet as I've only signed up newly to stardot).

I can see you have a listing on eBay but the postage for me is listed as GBP 41.01 (approx. AU $74.66). Is there a cheaper way to order? (particularly postage).

Also, I'm in a situation where I cant use the RGB output of my BBC as I have no monitor handy that is capable here (downunder in Australia).

From what I understand the composite / RF out wouldnt show any colour. Do you think its feasible to modify the composite out of a BBC using a circuit based on AD 725/ AD 723 (http://www.analog.com/media/en/technica ... /AD725.pdf) ?

Thanks!

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Re: VideoNuLA boards

Post by danielj » Tue Sep 18, 2018 7:15 am

If you can get hold of a GBS8200 (dirt cheap), they take RGB in (via resistors in the cable to bring the TTL levels down) and will output pretty good quality vga to an LCD. Works well with the NuLA.

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Re: VideoNuLA boards

Post by RobC » Tue Sep 18, 2018 8:13 am

jmc wrote:
Tue Sep 18, 2018 6:23 am
Great work on the VideoNuLA! Boy oh boy, how we all wished we had something like this back in the day! Incredible.

I have two questions about ordering (can't PM yet as I've only signed up newly to stardot).

I can see you have a listieedbackng on eBay but the postage for me is listed as GBP 41.01 (approx. AU $74.66). Is there a cheaper way to order? (particularly postage).
Thanks for the feedback.

The price on here is lower and so is postage as eBay virtually forces me to use their Global Shipping Program for overseas postage.

I'll PM you with my contact details.

I haven't tried to route the VideoNuLA output through a GBS8200 but I'll take Daniel's word for it that it works.

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Re: VideoNuLA boards

Post by trixster » Tue Sep 18, 2018 8:25 am

I’ll second Daniel - I’m using a gbs8200 with a videonula and it works well if you can forgive the 60hz output.
A3020 | A3000 | A420/1 | BBC B + 128K RAM/ROM + 20K Shadow + Pi0 + VideoNuLA
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Re: VideoNuLA boards

Post by danielj » Tue Sep 18, 2018 8:28 am

Just looking at that ic you list, it looks like it should work but you'll have to tap vsync and hsync from somewhere (the 6845?) as you only get csync at the rgb output.

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Re: VideoNuLA boards

Post by jmc » Tue Sep 18, 2018 9:03 am

danielj wrote:
Tue Sep 18, 2018 7:15 am
If you can get hold of a GBS8200 (dirt cheap), they take RGB in (via resistors in the cable to bring the TTL levels down) and will output pretty good quality vga to an LCD. Works well with the NuLA.
Thanks for the tip, I'll give that a try.

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