exxos's DFB1 trials

[exxos]

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[exxos]

So I uninstalled the removed the driver for the cable. rebooted and let windows pick it up and now it works. That was the TL;DR version!

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[exxos]

Well that didn't work then I will have to send you a board @Badwolf and check my firmware updates as I must have borked something up

I assume the firmware you said use doesn't need to disable the flash ROM or something stupid ?

The first oopsies on the board build is the "option headers" are to short. But shorting DISABLE does allow the falcon to boot and the LED's do change when I press reset. So the firmware seems good, just isn't running

EDIT:

OK it boots if I use the FLASH jumper, which I assume disables the flash.

[exxos]

Quick tests to make sure 40MHz and 50MHz modes work.

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Now to plug in the FPU

Just need to have a couple shots of Vodka first..

[exxos]

Damn!

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But thing is one FPU fails right away 40 or 50Mhz. This one fails randomly within the first few tests at 40MHz, and fails on the first test everytime at 50MHz. I chucked freezer fpray on it and made things worse

The problem before was it always failed on the same test, *somewhere* towards the end. But think that was when running from its own OSC. These tests are "PLD driven". Using the buffer didn't seem to make any odds.

So currently I think these 40MHz stamped FPU's are not actually 40MHz!

EDIT:

Saying that , @Badwolf doesn't your code half the clock on the FPU by the look of it ?

EDIT2:

Ah yep its going via the PLD at half clock speed. Will take that out and try again...

[frank.lukas]

My experience is that an FPU on the DFB1 Atari Falcon Speeder does not work properly at all.

[exxos]

@Badwolf So currently, it passed the first test, then "hung" on the second with the white LED on, which looking at the code is FPU_CS. DSACK0 is high and DSACK1 is pulsing low. TOS is still running as the cursor is still flashing. So its like the CPU never "got" DTACK

[exxos]

40MHz FPU

I did swap the FPU about a few times (only 2 testing) but now its working fine for no reason at all ?!

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I checked the FPU clock was 40MHz on my scope!

EDIT:

Reflashed my firmware, reset, and now failing again

EDIT2:

Ahhhhhhhhhh I know what I did now

I added a DTACK delay then removed it, I put it back in, working again. So one of my FPU's is buggered, and the CPU I presume is reading DTACK from the previous bus cycle which I made code changes to avoid.

[exxos]

40MHz CPU & FPU.

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[exxos]

40MHz CPU & FPU in ALT-RAM. (with "random" version of MAPROM)

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