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-   -   A500 logic analyzer tests (http://eab.abime.net/showthread.php?t=36843)

Toni Wilen 23 May 2008 20:43

A500 logic analyzer tests
1 Attachment(s)
This is probably better forum than uae wishlist..

Attached is first 20 or so DMA access cycles in scanline.

Also regular A->D (70=BLTADAT, 0=BLTDDAT) blit is active at the same time (easy to see free cycles)

3C = Horizontal sync strobe (note long time between strobe and real hsync signal changing state)
Following 3 x 1FE = refresh slot (strobe is first refresh)
26 = disk DMA (x 2, 3rd slot is free. Test was enabled disk write to non-existing disk)

Everything matches 100% with diagram in HRM. (so boring.. I'd have expected some differences..)

Only problem is matching VPOSR hpos=0 position. (I'd expect it to be strobe position but it may not be exactly right)

Zetr0 24 May 2008 03:09

Fascinating, :shocked

what mischief are you upto Toni?

Photon 30 June 2008 17:52

He's making sure the science gets done, like real men do. :cool

Yeah, would have been interesting to see any deviance from HRM, many have claimed to have experienced errors.

Either way, on limited hardware it's crucial for optimum performance to know the exact behavior, not only "how to code this to do that". One example on recent platforms is knowing exact behavior of caches and memory interfaces, now that DMA plays a smaller role.

Gonna write a thread in prb.hardware for a project now :) cos I finally got paid...

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