HP 8594E Replacing the green CRT with LCD

[BrianHG]

You are loosing the top few lines in NTSC where the HP logo is and the clock.  But, I guess it is to be expected if HP decided just to drop the ~50 missing lines of video instead of having scaled graphics.  Otherwise, your LCD panel is dropping those lines out.

[Miti]

You are loosing the top few lines in NTSC where the HP logo is and the clock.  But, I guess it is to be expected if HP decided just to drop the ~50 missing lines of video instead of having scaled graphics.  Otherwise, your LCD panel is dropping those lines out.

That's exactly how it is presented by the instrument, my LCD does not cut anything, see below. Actually there is enough room for the entire image, I don't know why HP decided to cut their logo in half. If my counting is correct, there's only 238 visible lines in NTSC mode, 263 in total with VSync, BP and FP. The clock is there, take a closer look.

What's left, is to save and recall the color scheme in/from the EEPROM so it starts with the latest scheme instead of a default one. Since I have the code tested, it shouldn't take me more than 30 min to add and test the module, I just need to find the time and the will.
Next step is to make a board, my first board in Kicad, with all the components on the top side (fingers crossed) so it gets assembled by JLCPCB. I don't think two layers is enough but I should be able to place everything on the top layer.

[Bud]

That's exactly how it is presented by the instrument, my LCD does not cut anything, see below. Actually there is enough room for the entire image, I don't know why HP decided to cut their logo in half.

BrianHG is correct, you are missing the top of the screen. HP did not cut their logo. This is what it should look like:

[Miti]

BrianHG is correct, you are missing the top of the screen. HP did not cut their logo. This is what it should look like:

Nope, you are not in NTSC mode. What you show me is either NRM or PAL mode. Take a look at my three pictures in the previous page and the picture in this page, which is a screen shot from the CRT.

[Bud]

Can you see the top on gpib screen capture when in this mode?

[Miti]

Can you see the top on gpib screen capture when in this mode?

GPIB capture does not follow the screen. See below.

[BrianHG]

One positive side effect of using Brian's idea of digital PLL with DDIOs in the FPGA is that it doesn't need a feedback clock divider as it would if I used MK9173, for example. That means that as long as the HSync pulse is aligned with 4x the 42MHz clock, it would generate the correct 42MHz frequency regardless of the front porch, back porch or active pixels on the line. That means it should work in all 3 video modes that HP8590 can output, NRM, PAL and NTSC. And it does, see below. It's getting better and better.

The bigger plus is if your sync disappears or is missing, the 42MHz will automatically continue to oscillate at 42MHz as accurate as your system reference crystal oscillator.  The other external PLLs would go haywire or produce frequencies which your output graphics would not be able to generate a displayable image from.

[Tony_G]

BrianHG is correct, you are missing the top of the screen. HP did not cut their logo. This is what it should look like:

Nope, you are not in NTSC mode. What you show me is either NRM or PAL mode. Take a look at my three pictures in the previous page and the picture in this page, which is a screen shot from the CRT.

This seems to be the part of the manual that Miti is referring to - Used to have one of these but I moved over to an 8563E so I can't provide any more info than this.

TonyG

[Miti]

This seems to be the part of the manual that Miti is referring to - Used to have one of these but I moved over to an 8563E so I can't provide any more info than this.

TonyG

Thanks TonyG for finding that, I did not read that before, all my posts are based on my observations. Interesting is that I don't see that compression on PAL format, I only see it on NTSC.

[BrianHG]

In PAL, the lines are there, but they are located in the overscan region.  So, on many PAL TVs, that portion of the picture may be off the edge of the screen, but on a monitor, they may still be there.

[Miti]

Well, it took waaay longer than I expected but Rev 1 boards are here. I just reassigned some pins that were different than my prototype and brought the first one up and it works perfectly. I missed couple of ground connections, nothing that couldn't be fixed with a solder bridge or a wire. I still need to find better, of the shelf connectors/cables in two locations, but other than that seems to work fine. Color scheme can be selected with jumpers or with an IR remote, through the focus adjustment hole.
Once I clean up the code a bit, I'll work on an easy mechanical solution to install the adapter and the LCD inside the analyzer.

[sp9bsl]

Hello Miti,
will you share the project files or is it intended as commercial?

[Miti]

I would like to put together a kit as a cheaper solution than Simmconn Labs's NewScope-0Jr, which is quite expensive, in my view. Of course, it includes all the HW needed, but many people just want the adapter. I'll see how feasible is to make a kit, or sell as adapter plus cables only.

[Miti]

Looking at the VGA output, it doesn't look too bad but I wonder if I can improve it a bit by playing with the current strength of the outputs. The current strength is set to "8mA (default)" but there's a "Maximum Current" setting which I cannot find what is anywhere. Do you know what is the maximum current strength of Cyclone?

[bitseeker]

Hi Miti,

Just found your thread. Very interesting project and looks like great results thus far. I was already impressed with the simple B&W version and the color is even better.

I have an 8560E and an 8924C, so CRT replacements are in my future and I was curious what the current state of your project is.

[Miti]

Hi Miti,

Just found your thread. Very interesting project and looks like great results thus far. I was already impressed with the simple B&W version and the color is even better.

I have an 8560E and an 8924C, so CRT replacements are in my future and I was curious what the current state of your project is.

Hi bitseeker, thanks for your interest!
My project is on hold right now due to the chip shortage. I can’t find FPGAs at a reasonable price. LCSC has zero stock on almost everything I need. Also some switching regulators are on back order at Digikey. 
I also have to figure out the mechanical side but I kinda lost interest.
However, my adapter is NOT compatible with the 8560 series, it is only compatible with the 8590 series.

[BrianHG]

Cyclone IV in 256pin BGA are available at a few places like Bristol Electronics.  But who knows for how long.
The chip shortage will last another 2 years, so be patient.

[bitseeker]

Hi Miti,

Just found your thread. Very interesting project and looks like great results thus far. I was already impressed with the simple B&W version and the color is even better.

I have an 8560E and an 8924C, so CRT replacements are in my future and I was curious what the current state of your project is.

Hi bitseeker, thanks for your interest!
My project is on hold right now due to the chip shortage. I can’t find FPGAs at a reasonable price. LCSC has zero stock on almost everything I need. Also some switching regulators are on back order at Digikey. 
I also have to figure out the mechanical side but I kinda lost interest.
However, my adapter is NOT compatible with the 8560 series, it is only compatible with the 8590 series.

I can understand getting a bit burned out. The chip shortage is a good reason to take a break. It's a very cool project, though, and I totally understand that it's designed specifically for the 8590 series. The project is still inspiring and could be the conceptual basis for bringing new life to other CRT-based equipment, which is why I mentioned a couple of my CRT-based gear as examples.

I'm hopeful that projects like this will be able to continue to save our old equipment from the landfill.

Cyclone IV in 256pin BGA are available at a few places like Bristol Electronics.  But who knows for how long.
The chip shortage will last another 2 years, so be patient.

Yeah, patience is a virtue these days. I don't foresee any of my CRT-based TE burning out in two years, but time will tell.

[BrianHG]

Lattice LFE5U-25F is still available from multiple sources like Digikey, Mouser, Element 14, Farnell..., but, it is overkill for this project even though the price is good.  The LFE5U-12F would have been a good fit.

But with 1 megabit core memory, you could have very colorful graphics and still cost less than the smallest Cyclone IV.

[SiliconWizard]

Lattice LFE5U-25F is still available from multiple sources like Digikey, Mouser, Element 14, Farnell..., but, it is overkill for this project even though the price is good.  The LFE5U-12F would have been a good fit.

It's not available anymore here on Mouser. But if it is elsewhere, good. Overkill but still rather cheap and if available...

Note that - as discussed in another thread - the 12F is actually the exact same device as the 25F internally. Except for a device ID number. It's just sold at about 30% to 50% less. Marketing.
If you're using Lattice tools, you won't get a full 25F with a 12F, but if you use open-source tools such as yosys/nextpnr you will.

[BrianHG]

Will you look at that, stock:
https://www.digikey.com/en/products/detail/lattice-semiconductor-corporation/LFE5U-25F-8BG381C/5358091?s=N4IgjCBcoLQExVAYygFwE4FcCmAaEA9lANogCsIAugL7X4KSkAyAYgKJkCq8FNQA

Though its the fastest -8, so the price is high.

This chip shortage is like begging for scraps.

[bitseeker]

This chip shortage is like begging for scraps.

And paying extra for it.

However, it's still OK relative to how expensive the commercial LCD-based solution is.

[Miti]

As an exercise in futility and to prove myself that I'm not bipolar (I read somewhere that starting many projects without finalizing them could be a sign of bipolar disorder... raise your hands those with symptoms, mine is up) I decided to finalize (at least) this project. The 3D printer that I acquired awhile ago and was collecting dust for about a year was put to work and the result is quite good. I made a bracket that holds the LCD, the LCD driver board and my adapter. I also redesigned the front display frame to accommodate a 5.6" LCD module and the different spacing of the buttons menus on the LCD. It also brings some fresh air to the front panel compared to the original dark frame.
I've checked again LCSC and Digikey and, to my surprise, most of the parts are available again at reasonable prices and with healthy stock, except for the most important one, the FPGA. Hopefully it will be available soon. With a bit of redesign, some parts are not available anymore in the same package, I think I can revive this project and make it available for those interested. Please enjoy some pictures...

[Miti]

Some more pictures.

[jwrodgers]

Hi Miti,

Very interesting and great work. Thank you so much for sharing the project you have been working on for so long.

I have recently bought an 8590 with a dead CRT screen, and would love to be able to get the hold of one of your converter boards and LCD to go with it. I have a 3d Printer, so could do all the mounting bits.

Have you considered making it commercially available, or would you have one or two spare boards that I could purchase from you?

Thanks,
JR