BeebSCSI 7_7

for bbc micro/electron hardware, peripherals & programming issues (NOT emulators!)
cmorley
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Re: BeebSCSI 7_7

Post by cmorley » Sun Jul 15, 2018 8:27 pm

danielj wrote:
Sun Jul 15, 2018 8:13 pm
Don't use superglue. Top tip.
Kragle is superior :)

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1024MAK
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Re: BeebSCSI 7_7

Post by 1024MAK » Mon Jul 16, 2018 6:59 am

cmorley wrote:
Sun Jul 15, 2018 7:26 pm
1024MAK wrote:
Sun Jul 15, 2018 7:04 pm
Just to add to the confusion, the normal description in the U.K., is that for the normal dual pin IDC connectors, the PCB mounting part is the male plug. The connector that fits the male plugs, that attach to ribbon cable are line sockets.
I am not sure that is right...
Isn't a PCB box header a receptacle with pins and the cable end a plug with sockets?

Pins and sockets describe the individual connection's terminals. Plugs and receptacles describe the connector as a whole. You can have plugs with pins or sockets and receptacles with sockets or pins... all the combinations.
So what do you call the PCB mounting part when you just have the pins and no surrounding plastic? It makes no sense to say I plugged the plug into the pin header...

The definition is normally based on the electrical contacts, not the plastic/insulated/metal case.

Mark
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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Mon Jul 16, 2018 9:07 am

And it is these reasons I have a large box of bits where I have order the wrong angle, gender, pitch etc etc.

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Jul 20, 2018 10:15 am

Nearly finished putting together parts order list for v7.7. 2 questions, all to do with holes.

What do I need to order for:

Fiducials:Fiducial_0.5mm_Dia_1mm_Outer

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simoni
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Re: BeebSCSI 7_7

Post by simoni » Fri Jul 20, 2018 10:38 am

Fiducials are alignment markers used for board production when using pick and place machines - it is not a 'component' that needs to be purchased; it's an optical marker on the PCB surface.

https://en.wikipedia.org/wiki/Fiducial_ ... uit_boards

The board contains 3 such markers (F1, F2 and F3) and actual 4 mounting holes (MK1-MK4).

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1024MAK
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Re: BeebSCSI 7_7

Post by 1024MAK » Fri Jul 20, 2018 1:22 pm

Elminster wrote:
Fri Jul 20, 2018 10:15 am
Nearly finished putting together parts order list for v7.7. 2 questions, all to do with holes.

What do I need to order for:

Fiducials:Fiducial_0.5mm_Dia_1mm_Outer
Tipex? :lol:
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1024MAK
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Re: BeebSCSI 7_7

Post by 1024MAK » Fri Jul 20, 2018 1:25 pm

Duncan, all joking aside, good luck with the various projects.

If everything works out, are you intending on posting up your BOMs?

Mark
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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Jul 20, 2018 6:56 pm

Could do. Half of them RC2014 boards. I then have 3 beebscsi and freewifi to build for acorns.

Edit: oh and working on the usb to electron header single cable thingy
Last edited by Elminster on Fri Jul 20, 2018 7:21 pm, edited 1 time in total.

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Jul 20, 2018 6:57 pm

simoni wrote:
Fri Jul 20, 2018 10:38 am
Fiducials are alignment markers used for board production when using pick and place machines - it is not a 'component' that needs to be purchased; it's an optical marker on the PCB surface.

https://en.wikipedia.org/wiki/Fiducial_ ... uit_boards

The board contains 3 such markers (F1, F2 and F3) and actual 4 mounting holes (MK1-MK4).
Explains my confusing. Being in the BOM I was scratching my head. Was wondering how I was going to buy holes.

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danielj
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Re: BeebSCSI 7_7

Post by danielj » Fri Jul 20, 2018 7:06 pm

In KiCad it's a good idea to tie a footprint to something in the schematic, otherwise when you reload the netlist in the PCB editor it'll go AWOL :) . Once something's in the schematic it gets yoinked into the BOM when that's created.

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simoni
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Re: BeebSCSI 7_7

Post by simoni » Fri Jul 20, 2018 7:28 pm

I was following some good advice from a fellow Acorn fan who worked for a company that did pick and place assembly. Placing the fiducials in the schematic helps them to identify the markers during the process. Also, as Daniel states; it's generally a good idea to have everything in the schematic as well as in the PCB design.

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Jul 20, 2018 7:44 pm

That is okay I found a cheap seller of holes on eBay :wink:

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1024MAK
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Re: BeebSCSI 7_7

Post by 1024MAK » Fri Jul 20, 2018 8:36 pm

Elminster wrote:
Fri Jul 20, 2018 7:44 pm
That is okay I found a cheap seller of holes on eBay :wink:
Polomints?

Mark
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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Sun Jul 22, 2018 7:44 pm

Last one that had me scratching my head was that J3/J4 are the same connector and labelled JTAG.

So looks like my grand total for 3 boards (with some spare bits left over and some bits I had) is £64.36, i.e. about £22 each.

Is that what other people got?

I have Xlinx and Altera programmers. Looks like I need to get an atmel one now as well.

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simoni
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Re: BeebSCSI 7_7

Post by simoni » Sun Jul 22, 2018 8:15 pm

In the 7_7 design both the CPLD and AVR are joined in a JTAG chain, so there is only one JTAG header for both chips.

The reason there are two headers labelled JTAG is that one is a standard 10 pin JTAG header suitable for both AVR and Xilinx programmers and the other is a tag-connect header. Tag-connect is a header that doesn't require any component mounted on the board; so, when making many boards, it can cut the production cost - however you have to have a tag-connect header cable (which is about 50 euros one-off cost). This is why I included the standard header too.

On another note, yes you will require both a CPLD and AVR programmer (both JTAG capable).

All of the above is covered by the documentation: https://www.domesday86.com/?page_id=439

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Sun Jul 22, 2018 9:35 pm

Okay thanks. I will order an ICE Basic as well.

Doubles the price of the board (for 3) but hopefully I will get to use it for other boards as well.

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simoni
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Re: BeebSCSI 7_7

Post by simoni » Mon Aug 06, 2018 11:10 am

I've now added a 3D printable case for the BeebSCSI board to the Github (both OpenSCAD and STL files are available). The case is completely reconfigurable in openSCAD (you can change the size, ports and decoration):
1.jpg
Note that the BeebSCSI board requires all connectors to be right-angle (except the power connector which should be straight) in order to fit the case correctly. The case is held together by 2x M3 counter-sunk head screws.

aotta
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Re: BeebSCSI 7_7

Post by aotta » Thu Aug 09, 2018 6:16 am

Really nice! Time to save money for a 3d printer...

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