AMIGA alive

AMIGA alive
Showing posts with label vga. Show all posts
Showing posts with label vga. Show all posts

Saturday, February 13, 2021

How Amiga is a NEC Multisync LCD1970VX monitor?

Whenever a LCD monitor comes around, it's worth testing if it's suitable for Amiga use. According to sources, this one partially supports Amiga screenmodes - I gave it a try, or two.

Let's quickly run down the features of the monitor. This is the "partial support" information gathered from famous website 15khz.wikidot.com: 'No practical evidence. I kindly ask author to provide more information. Support is considered "Partial" for now. "Full" can be after test.'

Here's what the device looks like on the outside, and some specifications:

The NEC Multisync LCD1970VX has a nice front panel with four buttons and mini-joystick (sorry, bad picture)
The stand has room for cable routing, can be rotated, and is height adjustable (spring supported). Display can be tilted. Cable installation and position adjustment is smooth and easy - great stand!
Mains switch and input, and type label

DVI and VGA video connectors - an adapter for Amiga RGB video output is required

It's a 19 inch display, picture aspect is 5:4, and here's a 1280x1024 pixel screen from a Linux laptop:

Linux laptop VGA output, 1280x1024 pixel display mode

How does it perform with the Amiga?

For testing we're using an Amiga 1200, Commodore RGB to VGA adapter (DSUB23 to DSUB15), and VGA cable (DSUB15 to DSUB15), which is connected to the monitor's VGA input. On boot, the Amiga's Workbench is set to "PAL:High Res" 640x256 pixels, default overscan / screen size. For now, we won't change monitor settings manually, and let the monitor do all sensing and adjustments.

There's a picture!
Well, not bad! A (halfway) modern LCD monitor displaying some Amiga-native screenmode is a rare sight. There seems to be something a little off about the pixel clock or phase or something, the screen has slight vertical stripes. Also fonts look a little distorted, maybe due to scaling. Setting some background color, it becomes visible that Workbench screen size doesn't fit display size:
For "PAL:High Res" screenmode, the monitor chooses 640x240 pixel display mode

Ok, let's go through some more screenmodes - "PAL:High Res Laced" next. It shows up quite like the previous mode, but interlace flickering is strong. This might be acceptable for some games, but it quickly gives you nausea when using Workbench and fonts, and is probably completely useless for graphics work with DeluxePaint or the likes. 

"PAL:High Res Laced" screenmode - interlace flicker
"PAL:Low Res" and "PAL:Low Res Laced" screenmodes work as expected: same Workbench area visible, same screen position, same monitor display mode, just pixels double wide.

Same results with "PAL:Super-High Res" and "PAL:Super-High Res Laced", just pixels half as wide, here's what it looks like:

"PAL:Super-High Res" screenmode
"PAL:Super-High Res Laced" screenmode - interlace flicker

We go a little bit more into PC and VGA territory with "MULTISCAN:Productivity" screenmode, with "VGAonly" put into "Devs:Monitors". The monitor almost gets it right, with just a few lines missing at the bottom.

"MULTISCAN:Productivity" screenmode

Most other screenmodes are displayed quite similarly. "NTSC" screens are fully visible (no missing lines at the bottom) and there's very little vertical striping, but position is off. "EURO:72Hz Productivity Laced" looks pretty good: interlace flickering seems to be far less noticeable here. Without "VGAonly", display of the respective screenmodes is a bit off, and in case of "DBLPAL" the monitor complains about frequency range and tries to auto-adjust. Overall, sometimes a message would pop up notifying about the monitor's native resolution - indicating that the signal received isn't perfectly within limits.

"NTSC:High Res" screenmode - fully visible, but not centered

"EURO:72Hz Productivity Laced" screenmode - less interlace flickering compared to other interlaced modes

Some screenmodes are not working at all:

  • "EURO:36Hz" non-interlaced: no picture, frequency out of range
  • "A2024" modes: picture corrupted

"A2024" screenmodes - umh, nope...

So far, so good. So the monitor works when connected to the Amiga, but "out-of-the-box" pretty much none of the screenmodes are displayed flawlessly.

But then... surprise!

Surprisingly, when switching back to "PAL:High Res" from some interlaced screenmode, the entire Workbench area is now properly visible, both horizontally and vertically.

"PAL:High Res" screenmode - now with 800x300 pixel display mode!

I couldn't figure out what precisely causes the change in display mode. There seems to be some sort of limit, which if exceeded causes the monitor to adjust itself differently. Is it the interlacing of some other modes, or some specific higher vertical resolution?

"PAL:Super-High Res Laced" screenmode, 800x300 pixel display mode

Manual tweaking - better results

Until now there was no manual interference with the monitor settings involved. Certainly better results can be achieved with some tweaking. Using the monitors menu button and mini-joystick, the picture's vertical position, horizontal position, and horizontal size can be adjusted. (And colors etc.)

This is the best result I could achieve with "PAL:High Res" screenmode - vertical size adjustment would be nice:

"Best possible" in "PAL:High Res": display resolution switch trick, horizontal size, horizontal position, and vertical position adjusted

"Best possible" in "PAL:High Res", detail from the same screen as above: due to horizontal stretching the vertical stripes become less noticeable, but uneven pixel scaling becomes more visible
(Moire effect caused by photo camera, not display)
And here's a big Workbench using "EURO:72Hz Productivity Laced", which misses only two or three lines of pixels at the bottom:

"Best possible" in "EURO:72Hz Productivity Laced": horizontal size, horizontal position, and vertical position adjusted

The NEC LCD1970VX seems to remember size/position settings, but these apply to all display resolutions, so the picture will probably be off again when switching screenmode.

So is it usable?

Yes and no. It really depends on how you use your Amiga. Amiga-native screen modes' picture quality is average to acceptable. Of course the monitor displays true VGA modes from a PC or Amiga graphics card perfectly. ("MULTISCAN:Productivity" with "VGAonly" and size/position adjustment). The main issue is the switching of monitor display resolutions - depending on what you want to do, this might give you an oddly positioned picture, maybe bad flickering, and spoil the fun. Imagine if you're a gamer, and need to change Workbench screen resolution a couple of times before "PAL:High Res Laced" becomes fully visible, ready to display your game's title screen. Certainly not a desirable setup.

But one can imagine two scenarios where this monitor might be quite welcome:

One is, if you're a Workbench-only Amiga user. You can choose and save some "MULTISCAN:Productivity" screenmode, or "EUR:72Hz Productivity Laced" as shown above, adjust monitor settings, and have a very usable picture on boot and for working. Even better if you have a graphics card with a pass-through connector, this monitor will at least display something when you occasionally need to show some Amiga-native screen.

The other is "lab" work - experimentation, multiple, and different computers. This is where this monitor could be really helpful, as it obviously accepts quite a wide range of signals, and has VGA and DVI inputs. It might also save some serious space on your desk. Unfortunately, composite video / SCART / S-Video inputs are missing - with these, it would really be versatile.

Additional sources:
http://15khz.wikidot.com
https://www.cnet.com/products/nec-multisync-lcd1970vx/specs/

Wednesday, September 19, 2018

The awesomeness: Amiga hardware news - galore! (2/2)

Even more pure awesomeness. The Amiga community is without a doubt the most active and knowledgeable in the retro scene.

Paul Rezendes' Amiga 4000 replica mainboard


We've already reported about this project - and, yeah, it's done, thanks to Paul and the community!

The GoFundMe campaign has reached and even exceeded the amount of money required, and Paul Rezendes was pretty quick at getting the first boards produced and tested. By now the files created have been released to the public, and you can even order a board from Paul.

https://github.com/Acill/A4000RevB/blob/master/Images/20180804_091312.jpg?raw=true

Another fantastic addition to the range of newly available Amiga parts. Now there's no excuse not to resurrect your battery-leakage-damaged Amiga 4000 from the attic!

The fundraising campaign can still be found at:
https://www.gofundme.com/amiga-4000-replica-with-schematics/

The files required to build your A4000 replica mainboard can be found at:
https://github.com/Acill/A4000RevB

Take a look at Paul's website for some pictures of these beauties, and order a board if you like:
http://www.acill.com


...and arananet's Amiga 4000 daughterboard!


With the Amiga 4000 replica mainboard done (see above), and John Hertell's A3660 Amiga 4000 CPU board done, you might be wondering "cool, but I still can't build my Amiga 4000 without a ..."

Daughterboard. Wonder no more.

Eduardo Luis Arana has published the files required to build a updated daughterboard. The ISA ports has been removed, and it now includes a 15KHz VGA display connector to use with a breakout / backplate bracket. And it has some nice fiery design on the backside.

https://github.com/arananet/A4000db/blob/master/img/1.png?raw=true

You can grab the files required build your new Amiga 4000 daughterboard from GitHub at:
https://github.com/arananet/A4000db


Amiga S-video board


The Amiga's video connectivity features, while being highly convenient about 25 years ago, have turned out to be somewhat problematic today, and every update to them is warmly received.

http://electronics.chroma.se/svideo2.jpg

This board connects the any Amiga's 23-pin display output, and has a composite video, an S-video, and a 15KHz VGA output connector. Picture quality is claimed to be higher than Amiga-built-in outputs, especially using the S-video output.

Here we have another little success story regarding teamwork among Amigans: this circuitry is the one being used in John Hertell's ReAmiga 1200 for video output - nice! (see part 1 of this article)

Go to this website for more information about the Chroma Amiga S-video board:
http://electronics.chroma.se/svideo.php


K1208 and A1200 SDE+ 8MB FastRAM, SPI (SD, Ethernet) boards for Amiga 1200


Derived from Stephen Leary's TF328 project by Kipper2k, and further developed by Solidcore and Mike Stirling, these are two similar expansion boards for the Amiga 1200.

The specifications read as follows:
  • 4MB/8MB FastRAM jumper (4MB for PCMCIA support)
  • microSD card slot, up to 4GB FAT95 (FAT/FAT32) formatted cards (SPI 8MHz)
  • Ethernet ENC28J60 SPI module support (SPI 8MHz)
  • Real-time clock
  • 2800+ dhrystones on stock Amiga 1200 (14MHz 68EC020)
The situation with these boards is a bit unclear, no conclusive information about final development and availability could be found. It looks as if currently only the software for the cards (drivers and firmware) has been released to the public.

If you want to know more, check these links:http://eab.abime.net/showthread.php?p=1212721
http://www.amibay.com/showthread.php?100275-A1208-8MB-Fastmem-SPI-(SD-Ethernet)-Board-for-A1200
https://www.mike-stirling.com/2018/05/sd-card-and-ethernet-on-the-amiga-1200/
https://github.com/mikestir/k1208-drivers
https://github.com/mikestir/k1208-cpld

(If you can clarify about the situation please leave a comment, thanks!)


Inexpensive A500 hard disk interface


A nice little addition for your quick harddrive needs might be this straightforward Amiga 500 harddisk interface. It requires a floppy disk to boot from and has been successfully tested with Kickstart 1.3 and 2.0.

Now this one has a feature that cannot be praised highly enough:
As you can see in the picture below, it has two expansion port connectors, one after another - the front one is an adapter to standard 2.54mm pin grid connector, and the other one is the pin grid connector mounted to the PCB. As the author says in the README file: "[...] future expansions will be developed with pin headers as their main connector." Huge sigh of relief. Finally someone starts to get rid of proprietary, hard-to-obtain connectors, and replaces them with widely available, future-safe solutions. One small step for an expansion board, hopefully one giant leap for Amiga-kind.

https://github.com/AmigaPorts/a500hdd/blob/master/doc/nib.jpg?raw=true


As of now the latest commit to the GitHub repository happened just 11 days ago, so this is apparently under active development.

The projects website is located at:
https://github.com/AmigaPorts/a500hdd




BONUS HARDWARE:

GRETA FastRAM/microSD/ethernet expansion board for Amiga 500


A couple of years ago, Martin "endofexclusive" Åberg from Sweden created GRETA, a Xilinx Spartan FPGA-based expansion board for Amiga 500. It's build to add 8MB SRAM, a microSD slot, and 10/100MBit ethernet controller to the Amiga. The project files have last been updated on August 1st 2016, and hardware programming is still incomplete - currently only RAM expansion is supported.

GRETA seems to be some kind of forgotten gem among Amiga hardware expansions - the specifications look fantastic, it contains all of the features one would like to have on a single PCB. As it seems, there's only some programming required to make things work.

https://github.com/endofexclusive/greta/blob/master/doc/mounted_components2.jpg?raw=true


Wouldn't that be a nice project to pick up and give it some love?

Looking at the other amazing expansion boards that have come out in recent years, probably even an unexperienced programmer would be able to add ethernet and microSD mass storage support to the device, there's plenty of material out there to study and learn from.

If you're interested, go to GitHub, and start building your GRETA:https://github.com/endofexclusive/greta

You may find more information about GRETA in this forum thread on a1k.org:
http://www.a1k.org/forum/showthread.php?t=54707
(currently a1k.org doesn't accept new member registrations)


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Thanks for reading!
Support Amiga hardware development!
Donate!
Buy stuff!

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This part 2 of this article - have you read part 1?

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If you spot an error please report by leaving a comment below.
If you don't, your comment is still appreciated. ;-)

Sources:
http://www.acill.com
https://github.com/arananet/A4000db 
https://github.com/endofexclusive/greta
http://www.amiga-news.de/en/news/AN-2016-04-00050-EN.html 
http://www.nemesiz4ever.de/board/thread.php?board=1&thema=11


Tuesday, September 18, 2018

The awesomeness: Amiga hardware news - galore! (1/2)

It sounds too good to be true, but in these cases it isn't a hoax. There is a lot, and may I repeat, A LOT going on in Amiga hardware world... In fact it's so much I've split this into two parts.

7-bit's SPI controller for the clockport


On April 24th 2018, 7-bit Retro Electronics announced a new product: The "SPI MasterBus CP" controller for the clockport.

SPI is a simple, flexible, fast serial data interface that allows multiple devices to be connected. It's used by numerous types of devices across all computer platforms, e.g. as an interface to memory card readers (SD, SDHC, CompactFlash, ...), ethernet controllers, flash memory, for CPLD programming, and many more applications.

That makes a fantastic addition to the Amiga's capabilities!

Here are some "SPI MasterBus CP" specifications:

Designed for Amiga A1200’s clock port
SPI bus clock speed: 25 to 195 kHz
Full-duplex data transmission
Up to 4 devices with Slave Select lines

Built-in software will allow you to manage several characteristics of the controller.

Here's an early video showing SD-card access in action:

https://www.youtube.com/watch?v=j7HeQqHj56o

Keep an eye on their website for full specifications, project progress, and availability:
https://retro.7-bit.pl/?lang=en&go=projekty&name=SPICP


Jeroen Vandezande's Amiga 1200+ mainboard


With increasing age, Amiga 1200 mainboards (among others) run the risk of taking damage from leaking capacitors, and of course over a timespan of about 30 years there are a lot of other factors that may shorten - or quickly end - a mainboards life.

Wouldn't it be nice to just have the opportunity to purchase or make a new one?

This is one of two projects (see below for the other one) recreating the Amiga 1200 mainboard, Jeroen's "Amiga 1200+" is an updated version with some changes.

The project is covered by Creative Commons license, and you are free to build your own mainboard!

Here's a list of changes compared to the original Amiga 1200 1D4 mainboard, taken from the project website:
  • Gayle, Budgie and the DRAM have been removed and the functionality has been moved to a daughterboard. This board can also contain a CPU.
  • Video output has been moved to a seperate output board. This board get all Lisa output signals and also all the typical Zorro signals. This means that an RTG card can be developed.
  • The PCMCIA slot has been removed and in the free space a power switch, boot selector switch (DF0:/DF1:) and a uSD card slot have been added. 
  • A single supply universal power input has been added. (15V - 36V)
    From this the following voltages are created:

    * 5 Volts: main power rail 5 Amp capable

    * 12 Volts: 1 Amp capable

    * 3.3 Volts: 0.5 Amp capable (for daughter boards)
    * 1.2 Volts: 0.5 Amp capable (for daughter boards)
  • Two PC standard 3 Pin fan headers are added to the board. 
  • Terrible Fire compatible SPI port for network chip 
  • Extension board connector for mouse/joystick. (One is in development that has USB Mouse and two classic DB-9 connectors and autoswitches when fire button is pressed.)

The "Terrible Fire compatible SPI port" is an especially nice addition: it shows that Amigans work together - way to go!

Now head over to Jeroen's website, and start building your enhanced Amiga 1200:
https://bitbucket.org/jvandezande/amiga-1200


John Hertell's Amiga 1200 replica and ReAmiga 1200 mainboards


The other project recreating the Amiga 1200 mainboard comes from John "Chucky" Hertell, well known Amiga hardware guru.

He had already created the A3660 Amiga 4000 replacement CPU module (see http://wordpress.hertell.nu/?p=537 and http://eab.abime.net/showthread.php?t=89200 if you want to know more), and asked the community for his next reverse-engineering project, which turned out to be the Amiga 1200 mainboard. Well, about two months later, and with the help of other members of the Amiga community, Mr. Hertell had a clone of the original 1D4 version mainboard in Gerber file format!

But he didn't stop there, adding some modifications to the board - here's a list of changes:
  • Supports round and square powerconnector
  • New reworked composite video logic, with additional S-Video support
  • RF-Modulator removed and replaced with optional buffered VGA connector
  • Selectable SEL signals for floppy
  • Optional NMI (IRQ7) possibility
  • Resetheader
  • A500 compatible keyboard connector (currently untested)
  • Support for the Ratteswitch with solderoles for required signals so no need of a socket on CIA
  • Extra powerconnectors for +12 and +5V fans, and extra powerconnector close to CPU slot
  • PCMCIA reset fix
  • Optional onboard LEDs where LED and +5V are separated also optional “opt” led, with jumperwire for PCMCIA activity LED
 
http://wordpress.hertell.nu/wp-content/uploads/2018/08/A1200pcb.jpg
Well, what can you say - another awesome job by Mr. Hertell.

Check his website for complete first-hand information, and files required to build your own Amiga 1200 or ReAmiga 1200 mainboard:
http://wordpress.hertell.nu/?p=587

Note that you can also buy ReAmiga 1200 PCBs from Mr. Hertell - income from these sales will partly be donated to Swedish children cancer fund. See link above.

 

Commodore Amiga AA3000 / A3000+ recreated


Both Matthias 'Matze' Heinrichs' and Christian 'Scrat' Euler have recreated a legend: an AGA-chipset equipped Amiga 3000!

Sadly, there's no open source re-creation (yet?) of the mainboard, probably due to technical difficulties (8-layer board) - but nontheless, this is another great example of the capabilities of the Amiga community. Who would've thought we'd see these ultra-rare machines outside of Commodore's laboratories one day?

Read the full story with pictures and files over at amiga-news.de:
http://amiga-news.de/en/news/AN-2018-08-00030-EN.html



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That's it for today - 

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If you spot an error please report by leaving a comment below.
If you don't, your comment is still appreciated. ;-)

Sources:
https://retro.7-bit.pl/?lang=en&go=projekty&name=SPICP
https://retro.7-bit.pl/?lang=en&go=aktualnosci&view=132
https://bitbucket.org/jvandezande/amiga-1200
http://wordpress.hertell.nu/?p=587
http://eab.abime.net/showthread.php?t=93015
http://amiga-news.de/de/news/AN-2018-08-00030-DE.html
http://www.bigbookofamigahardware.com/bboah/product.aspx?id=23