CURRENT PROTOTYPE STATUS (SEC 64MHz 68000)

[exxos]

tested on both STE and MSTE

[exxos]

Tiny update.. PCB's finally arrived Need to do a order to mouser and get the ATF chip and some other bits next...

sec-pcb.jpg (135.69 KiB) Viewed 7901 times

[exxos]

Small update.. Parts now ordered for this.. I'm going to ship the three boards and parts to a place in the UK for assembly as I just do not have time to do it. So hopefully in a few days time I can get the boards back and actually start working on the firmware.

Just as a re-cap, this board is the 68SEC000 test board, so I can see what the maximum speed of the CPU is. I am hoping to get it running at 50-64Mhz.

Even if the CPU cannot manage much more than the 68HC000 PLCC CPU, I will likely still use the SEC simply due to it is smaller, and a proper SMT package. With all the problems I am having with sockets, I have no choice but to move to a direct soldered part anyway. So moving to the 68SEC000 CPU is basically a good move anyway.

[exxos]

PCBs finally arrived... next to find time to finish firmware and test it.. but likely will finish the plug in STE booster first...

sec1.jpg (62.54 KiB) Viewed 7592 times

sec2.jpg (73.29 KiB) Viewed 7592 times

[exxos]

Finally cleared my table.. Now to work on the firmware..

IMG_2728.JPG (184.39 KiB) Viewed 7527 times

[exxos]

So something amiss, anyone any ideas whats going on here ?

dma.jpg (83.84 KiB) Viewed 7514 times

EDIT:

I tried removing AVEC from my code just to see what happens, and diag-cart says autovector error.. so that much be working... but still no idea whats going on with the DMA errors unless some sort of bus grant issue

[rpineau]

$FFFFFC00 and $FFFFFC02 are adresses for Keyboard ACIA .. so there might be something going on with VPA/VMA there.
The 2 other one are code on the cartridge port.

[exxos]

Its odd, because I see activity on VMA, but not VPA or AVEC ... but VMA shouldn't go low without VPA being low to start with ?!

[rpineau]

Is the E clock running properly ?
AVEC should definitely do something on interrupt from the keyboard. But if we can't write to the ACIA it probably doesn't trigger interrupt yet.
So it's really around VMA/VPA

[exxos]

Is the E clock running properly ?

Looks good on scope..

AVEC should definitely do something on interrupt from the keyboard. But if we can't write to the ACIA it probably doesn't trigger interrupt yet.
So it's really around VMA/VPA

No idea, I keep trying things, but no luck..

If I keep pressing reset, I see VMA pulse low.. though I half recall it does pulse more than VPA.. will have to re-read my notes tomorrow..

VPA I have trouble seeing any pulses.. but thats generated from GLUE anyway...

I don't get why diag-cart says DMA time out.. has nothing to do with CPU really