Writing ROMs for the Falcon

Various other hardware solutions.
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Badwolf
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Re: Writing ROMs for the Falcon

Post by Badwolf »

Rustynutt wrote: Tue May 18, 2021 11:57 pm Maybe I misread the data for it, thought it contained Falcon diagnostic as well.
That, or is the Falcon diagnostic image only 64k?
Hmm, good point. Some others must be 32k, then. Of course if it happens that the 128k exposed is at an address outside the 128k EEPROM you've bought that won't help.

In a single sentence, what are you actually trying to do? Get a 128k cartridge using a 128k PLCC?

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
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Rustynutt
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Joined: Fri Sep 29, 2017 8:24 am
Location: USA

Re: Writing ROMs for the Falcon

Post by Rustynutt »

Ordered the same as you have.
5PCS HN27C4096HCC-85 PLCC-44, erasable.

If I get everything else before it arrives, still have several OTP ROMS if I get impatient.

The UV eraser arrived yesterday.
XGecu TL866II Plus Programmer will be here next week. Went full tilt and purchased the package with enough adapters to rewire the house.

ROM's, at least in my Falcon Diagnostic cart are 256k each, and that's how the board is jumpered. Photo in above post.

Something I've learned in all this, is there are 64k areas times x for the various sizes. I'm not educated with electronics, only OJT and owning an Atari of one sort of another for 35 years :)
I,E, for a 256K ROM, thought it was just that, not divided up. Wasn't something I understood. I'd thought I could program HI/LO ROM regardless of either size, up to the addressable space of the cart port. Thank you all.

Don't know yet the size of the Falcon Diagnostic image, or the EmuTOS file size you used for development.
Will surely be pinging you soon for the EmuTos image :) Think copying the diagnostic ROM, and TOS ROM would be good places to start to learn the device.

Only reason I'm using the diagnostic now is to boot the Falcon into 25MHz (opposed to the COMBEL 16MHz output), getting around the Blitter. Mainly looking at the diagnostic timing results, how setting the COMBL output at "half speed" with the diagnostic, screen artifacts, any indicators the board isn't functioning at 25MHz bus. Poor man's logic analizer :)

Know it's been well thought-out years before with Nemesis/Phantom and many other speeders. It's just they rely on switching the clock after TOS is booted. Trying to get away from their design, and the additional fly wires it requires.
I'm looking at possibly using the IKB/MIDI ASCI pin 5's to control a switching logic for a single oscillator.
I've socketed those two now, and discovered alternate ways of injecting a 500KHz clock to them without uplifting pins for fly wires.
Through process of elemanation using the diagnostic cart, have discovered the lowest clock the Falcon will boot at. She happily boots with a 25MHz oscillator, which will be a 1/2 clock for 2x distribution purpose on the Afterburner.

The entire cartridge port use though now may not be necessary, at least for full EmuTOS/MagiC images. I'd purchased the Vulture ST RAM board. The sdram on Lotharek's card are mounted on the top, leaving plenty of room for a ROM extender cable/card to programming adapter such as you set up, or the ROM to cartridge port mod you ingeniously came up with.

Such is the life without CLPD :)
Did purchase a pair of 50/50 PGA 030/882 for when your design is fully available to build :)

I'd given away the last set with a new PAK/FRAK/Pulpa I'd given to a user in the hopes it would help the broader Atari community. I don't think he ever got it working, coming to the conclusion his Mega was at fault from the beginning of working with his original PAK.
I "guess" that was help, kind of hoped for more out of it. Was quite the investment...
Rustynutt
Posts: 224
Joined: Fri Sep 29, 2017 8:24 am
Location: USA

Re: Writing ROMs for the Falcon

Post by Rustynutt »

Single sentence :)
Received the diagnostic cart, the GEMBENCH program contained on ROM is under 64K.
Since I have two of these, may experiment changing the board.

Programmer arrived.
EEPROMS will take a bit longer.
Going to learn how to program some simpler IC's to get the hang of it.

Know about big/little endian, only enough to get me in trouble.

Say for example the Falcon bus GAL files floating around.
Have those already been swapped, or something required before programming?

Same for say the Falcon diagnostic ROM files.

Is that something changed due to being read with PC software package?

If using my Maxon Atari package, will reading a GAL, and then burning to another require any file maintenance, all things being equal?

Realize there is years of this info, Atari specific out there.
Rustynutt
Posts: 224
Joined: Fri Sep 29, 2017 8:24 am
Location: USA

Re: Writing ROMs for the Falcon

Post by Rustynutt »

Success!
Hitachi (5 pc's) HC27C4096 arrived.
Bathed them in UV light 60 min.

Had some issues with the programmer not reading the pins. Turned out, using the PLCC extractor buggered a pin.

This 44 pin PLCC to 40 pin DIL adapter has jumpers to take care of not having to wire it up as in the guide here.

Downloaded EmuTos 512k binary.
Spent an hour or more learning how to convert the file to big endian.
In the end, was simple. Already had Cygwin installed on a Win 7 box from years ago, updated and ran dd on the file
Worked perfectly.

Flashed the EPROM with the EmuTos binary. I'm using V11 of the soft for the burner, and it yet has to have the voltage changed to 12.5 and 50us as default, made that change.

Moved the EPROM over to the Falcon, booted right off!

Wasn't looking really to test EmuTos, but needed to get around the darn Falcon Blitter at boot.
Once to desktop, ensure Blitter is switched off and save desktop. Even with NVDI loaded, EmuTos can re-enable it.

With this was able to verify the Falcon can boot with a 50MHz oscillator.
No Nemesis :)

To run GEMBENCH had to remove the FPU above 40MHz. I've ran into this years ago, and oddly enough it all starts to work again with a 64MHz oscillator.
Need to rig up a separate clock for it.

IMG_20210607_184852.jpg
IMG_20210607_184852.jpg (311.96 KiB) Viewed 2602 times

Next test is to install an Eagle Sonic and test the CPU on the expansion bus at speed.

Then onto the Afterburner and see how fast it can be pushed.
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