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SuperMac Spectrum/24 Project

MacOSMonkey

Well-known member
I got the 40 & 50Mhz for $1 each. It would be nice to have a mini-LCD with an intuitive selector - maybe 3 digits and an M/K, etc.
 

Phipli

Well-known member
I got the 40 & 50Mhz for $1 each. It would be nice to have a mini-LCD with an intuitive selector - maybe 3 digits and an M/K, etc.
These exist, but I don't know how usable they are in terms of quality, cable lengths etc :


$1 is good going for small quantities! All my local wholesalers seem to have £20 minimum orders for free postage these days so I end up paying inflated prices on ebay.
 

Trash80toHP_Mini

NIGHT STALKER
@MacOSMonkey nice finds in the box rummage session! Are SuperMac and Seiko 16" resolutions 60Hz SVGA?

Early SuperMac cards, like Spectrum/24 1.0 implemented minimal slot manager support. In later SuperMac boards, there was the addition of "VDI" (Video Driver Interface) support, which theoretically allowed for certain additional/external configurability in conjunction with SuperVideo 3.0. However, the support also had to be in the firmware, and the earlier boards absolutely did not include it.
Interesting, is Video Driver Interface part of baseline Slot Manager/NuBus or the extended NuBus90 spec?

@Melkhior have you got anything on that subject or general observations on this insanity?
 

MacOSMonkey

Well-known member
I messed around with my Spectrum/8 Series II board a little this weekend and made a bunch of custom configs with SuperVideo. They didn't do anything -- it was just for testing. I have to wait until the oscillators show up. And yes, I think they are SVGA-ish. The Apple 15" monitor I have has 2 800x600 SVGA configs.

Per the Spectrum manual, I verified the cut-off for the clock divider for the TMS34061 on those early boards. As noted in the spectrum manual, the mid-range values (16Mhz+) are /8 by default and, at 52Mhz+, they are /16.

I looked at the 'cnfs' resources to match up the custom timing values with the resource data structure, and the divider bit is the first word. Referring to the TMS34061 manual, it maps to the low-order nybble of CR1. So, the default value for mid-range display updates is 0x07 or 0b00000111 (n+1, or updating every 8 clock periods)...or, for faster clocks, it is 0x0f or 0b00001111 (with the extra divider bit, n+1, or updating every 16 clock periods).

By the way, if you want to reset SuperVideo to no stored configs, just delete the 'cnfs' id 29000-range resources (or copy a new version of SuperVideo into your Control Panels folder).

The main thing about the above info is that, if you are trying to create a custom config within the capabilities of the board, don't forget to divide the H vidclk values by either 8 or 16 (or multiply the pixel clock time), depending on the custom frequency you are trying to use.
 

Melkhior

Well-known member
Melkhior have you got anything on that subject or general observations on this insanity?
If "Video Driver Interface" is something specific in that name, no. However, the video driver routines required are sometimes referred to as the "video driver software interface" (DCDMF3 p147). They did evolve over time; while the basic functions are the same, the numbers of selectors grew over time. The new ones, which I have seen called in 7.5.3 and 8.1 but not 7.1.1, includes cscSetDefaultMode, cscSwitchMode or cscSavePreferredConfiguration. There was a cscSetMode previously. IIRC, cscSetMode select among video resources where cscSwitchMode is meant to be more flexible - but I'm not 100% sure, as I didn't implement resolution switching, only depth switching, and for me both are pretty much the same.
 

Trash80toHP_Mini

NIGHT STALKER
Thanks much for the quick response and reference. Looks like it's back to the Technical Tomes for me while I work at getting the test setup put together.
 

MacOSMonkey

Well-known member
Early SuperMac boards supported a minimal-to-moderate set of control and status calls. And, as with any product line, there were various issues and bugs that improved/resolved over time, along with expanded features, control/status support and OS compatibility (i.e. A/UX). SuperMac's later feature add-on for its vendor-specific implementation of "VDI" (from ~PDQ timeframe forward, as I mentioned), allowed for external software updates to video board firmware (within certain limitations).
 

Phipli

Well-known member
What is the situation with these cards and PowerPCs. I think I read that the original PDQ and older boards don't work with PPC. I assume this means "at all" and not "work unaccelerated".
 

mg.man

Well-known member
I used to make these things :

IMG_20220910_091710.jpg


Two SMD clocks in the form factor of a DIP14 that you can toggle between.
Neat - have any left? :)
 

Phipli

Well-known member
This is missing from the list. This is a Spectrum/24 PDQ :

IMG_20220913_215704.jpg

The most chip heavy Nubus card I own.
 

Trash80toHP_Mini

NIGHT STALKER
Nice, thanks, posted! It was on the LEM list. PreterHuman has @LaPortas ColorCard with an incorrect picture. Can you take a shot of the Series III board that goes with your DaughterCard pic, that one's already up.

Back on topic:
I dug through my old junk boxes and was able to find and recommission a Spectrum/8 Series II ("Spectrum C") board (8-bit, 1024x768) with the original 1.0d14 ROM ("d" stands for "development," as you may know). It has 3 oscillator sockets, comes with 30.24Mhz (Apple 13") and 64.0Mhz (SuperMac 19" 60Hz) oscillators pre-installed. It is customizable based on built-in configs of: 640x480 (13", NTSC, Multisync), 1024x768 (SuperMac 19"), 768x576 (PAL), 800x600 (SuperMac 16" and Seiko), etc., with a max width of 1024 and max oscillator frequency of 64Mhz. Multisync mode uses 24Mhz, 16" uses 50Mhz (SuperMac) or 44Mhz (Seiko). I popped in a 55.00Mhz oscillator in the spare socket, the board detects it, and it shows up in SuperVideo. The monitor is an Apple Multisync 15 that supports SVGA/800x600, so I just need a 40 or 50Mhz oscillator to make it work at 60Hz or 72Hz vertical.
Can you read out the timing data for SVGA/800x600 from your board for me. Hoping to plug it into the setup for my board. ;)
 

Phipli

Well-known member
Nice, thanks, posted! It was on the LEM list. PreterHuman has @LaPortas ColorCard with an incorrect picture. Can you take a shot of the Series III board that goes with your DaughterCard pic, that one's already up.

Back on topic:

Can you read out the timing data for SVGA/800x600 from your board for me. Hoping to plug it into the setup for my board. ;)
You mean the one I cropped out of the photo? :ROFLMAO:

IMG_20220908_135805.jpg
 

MacOSMonkey

Well-known member
I haven't done the SVGA setup yet - maybe this weekend when the oscillators show up. I should be able to do both SVGA timings if everything works as expected. I may have to slap it on a scope - we'll see.

Phipli -- it was the most chip-heavy board because it used a bunch of Xilinx Virtex-3 parts to do the video acceleration - all the X parts. So, when you change bit depths, you will notice a slight delay, which is the time it takes the Xilinx parts to reload the acceleration code for the new bit depth. They were all eventually replaced by the SQ001 chip on the later PDQ, PDQ+, Thunder and other boards. But, this PDQ was faster than the 8-24GC, had 1152x870 support on 21" monitors, and was an integrated step forward from the PAL/GAL daughtercard-based design of the Spectrum/24 Series III.
 
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