DMA HEADER REV H1

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troed
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Re: DMA HEADER REV H1

Post by troed » Wed Dec 19, 2018 3:52 pm

PaulJ wrote:
Wed Dec 19, 2018 2:17 pm
I was thinking of taking the internal scsi board out of my MSTE and putting it in my mega 4. Both have the same number of pins but there were some differences. I didn't really check into the differences but I'm assumming it would work. We all now what happens when I assume. Always get burned!
The internal Mega STE ACSI and the internal Mega ST ACSI are not the same thing.
mega_st_internal_acsi.png
mega_st_internal_acsi.png (159.52 KiB) Viewed 1890 times
mega_ste_internal_acsi.png
mega_ste_internal_acsi.png (86.67 KiB) Viewed 1890 times
(It's the 24DRS and 30DRS connectors you want to look at, J17 and J402)

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PaulJ
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Re: DMA HEADER REV H1

Post by PaulJ » Wed Dec 19, 2018 4:09 pm

troed wrote:
Wed Dec 19, 2018 3:52 pm
PaulJ wrote:
Wed Dec 19, 2018 2:17 pm
I was thinking of taking the internal scsi board out of my MSTE and putting it in my mega 4. Both have the same number of pins but there were some differences. I didn't really check into the differences but I'm assumming it would work. We all now what happens when I assume. Always get burned!
The internal Mega STE ACSI and the internal Mega ST ACSI are not the same thing.

mega_st_internal_acsi.png

mega_ste_internal_acsi.png

(It's the 24DRS and 30DRS connectors you want to look at, J17 and J402)
Your absolutely right! Just went and checked the MSTE schematic, must have looked at too different mega st schematics. Definately a situation where I had my head up my arse. :oops: :oops: :oops:

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Re: DMA HEADER REV H1

Post by exxos » Thu Dec 20, 2018 8:04 pm

I used lotharek's header pinout here...


mst4.jpg
mst4.jpg (143.35 KiB) Viewed 1865 times

.. and added it to the STF ...

USDMA.jpg
USDMA.jpg (67.45 KiB) Viewed 1865 times

I'm not adding anymore headers for this now...
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Re: DMA HEADER REV H1

Post by Icky » Thu Dec 20, 2018 10:50 pm

exxos wrote:
Thu Dec 20, 2018 8:04 pm
I used lotharek's header pinout here...

.. and added it to the STF ...


USDMA.jpg


I'm not adding anymore headers for this now...
Plenty of options here Exxos - as you say don't need to add any more.

The USDMA header can be adapted with a small add-on board to provide the MegaSTE header. Could even pass Vcc to pin 20 for that board.

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Re: DMA HEADER REV H1

Post by exxos » Thu Dec 20, 2018 11:03 pm

Icky wrote:
Thu Dec 20, 2018 10:50 pm
Could even pass Vcc to pin 20 for that board.
I did wonder that, but we don't know if its connected US side to anything or not (ive not checked) it could be connected to gnd for example..
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Re: DMA HEADER REV H1

Post by Icky » Fri Dec 21, 2018 10:11 am

exxos wrote:
Thu Dec 20, 2018 11:03 pm
Icky wrote:
Thu Dec 20, 2018 10:50 pm
Could even pass Vcc to pin 20 for that board.
I did wonder that, but we don't know if its connected US side to anything or not (ive not checked) it could be connected to gnd for example..
Good point - I don't have an UltraSatan to check. Instead I have Gigafiles hence my looking at this header slightly differently as the Gigafiles can be powered directly off the MegaSTE / STacy DMA headers. Hence an adaptor board would work but obtaining a Vcc would make this a neat solution.

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Re: DMA HEADER REV H1

Post by exxos » Fri Dec 21, 2018 11:59 am

I can't remember if I posted images of this before or not..

Ultrasatan will *just* fit under the floppy drive. The is parts sticking up on US which are in the way of the chips on the MB, so I will need to arrange the chips carefully to miss the US parts..

IMG_3701.JPG
IMG_3701.JPG (124.38 KiB) Viewed 1834 times

The problem is there, its pretty low down...

side.jpg
side.jpg (46.28 KiB) Viewed 1834 times
1.jpg
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2.jpg
2.jpg (32.14 KiB) Viewed 1834 times


Putting US upside down however gets pretty close to the drive, so higher up which is good...

up2.jpg
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up1.jpg
up1.jpg (63.07 KiB) Viewed 1834 times

The maybe slightly annoying thing here, is if the US header was a vertical one, we would have a vertical header on the MB, so US would *almost* plug right into the MB header.. Though the chances of it all lining up perfectly is pretty slim I bet.

h1.jpg
h1.jpg (75.36 KiB) Viewed 1834 times

Thinking ahead, it should be a cable, even though annoying, as if US header moves even 0.1mm its no longer going to line up with the MB header anymore. Cable is annoying, but solves alignment issues and a lot of headaches.

Getting the chips on the MB to "miss" all the stuff sticking up on US will be tricky enough..
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Re: DMA HEADER REV H1

Post by exxos » Mon Dec 24, 2018 3:10 pm

I've been looking for a vertical header...

https://uk.farnell.com/multicomp/mc-254 ... dp/2843531

So assuming the one on UltraSatan is changed...

I actually have the 20 way connectors already from my Falcon RAM board :) these ones have long pins so the height could be adjusted into the new motherboard..

1.jpg
1.jpg (91.14 KiB) Viewed 1810 times

BUT...

I have these header spacers which lift the connector up a fraction...
2.jpg
2.jpg (39.61 KiB) Viewed 1810 times

It just so happens the height of the connector with the spacer, and the height of UltraSatan is exactly the same height (18.5mm) as the floppy posts...

3.jpg
3.jpg (69.83 KiB) Viewed 1810 times

So for those who have no idea what I am talking about... UltraSatan would be able to plug into the motherboard header directly without having to use a cable :)

It is just one massive fluke that the connector height and height of ultra Satan just so happens to be the exact same height as the floppy posts 8-)
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