BeebSCSImini

for bbc micro/electron hardware, peripherals & programming issues (NOT emulators!)
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flynnjs
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BeebSCSImini

Post by flynnjs » Wed Dec 06, 2017 7:51 am

A placeholder thread for people to raise any questions about the units that I'm posting out.

To kick off:

power. It needs power as no 5v is available on the 1MHz bus.

The BeebSCSI mini has space for a three pin power connector. You will need to connect
5v to the centre of this and 0v to either/both of the outer pins although in practice the
0v connection can be left unmade as this is provided through the 1MHz bus connector.

I have shipped many BeebSCSI mini board with a 3 pin header. However, due to some poor
planning on my part, some units only have two pins populated and one of the outer 0v pins
is missing. IT is not required to function but in this scenario please make sure you connect
the 5v to the correct pin.

Orientation of GREEN PCBs
Pin 1 is marked with a small white arrow on the silkscreen. If fitting under a model B
with no ribbon then all the components including the SD card should be visible when fitted.
It probably won't fit the other way around but don't try.

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danielj
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Re: BeebSCSImini

Post by danielj » Thu Dec 07, 2017 9:16 pm

Just to note, it won't fit under a master, you do need to use an extension cable (female-male 34 way IDC) or replace the header and use a straight 34-34 way cable.

For power on the Master, you may well find you're using it with the 80186 coprocessor in which case you're going to want the user-port for a mouse. Then 5v...I've used a spring clip to take +5v from the +ve side of R4 (the right hand side, looking at the keyboard from the front), passing the wire out of one of the holes between the IDC connectors, and then crimping a crimp terminal onto it. Clearly you can solder a wire on somewhere if you want and pass it out of the same place, or take +5V from somewhere else, but I'm all for not applying heat if I don't have to. :)

d.

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simoni
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Re: BeebSCSImini

Post by simoni » Fri Dec 08, 2017 3:32 pm

I posted this in the sale thread, but just in case, I'll repost it here (as it pertains to everything other than support relating to than Jason's superb boards) - apologies for the re-post, but I hadn't seen this new thread at the time:

Just a note to all the new owners of BeebSCSI boards - The BeebSCSI project is completely open-source and open-hardware - You are free to view and modify the source-code as much as you like (in fact, I positively encourage anyone with the know-how to do so). The same goes for the BeebSCSI ROM which is optional, but lets you use the 'jukebox' feature to provide as many hard drive images as you can fit on an SD card.

However, if you are not a microcontroller/CPLD boffin then you are most welcome to request feature enhancements (and bugs/issues should you find any) over on the project Github:

https://github.com/simoninns/BeebSCSI

Simply open a new issue and label it as enhancement/bug/question as appropriate. I can't promise any time-lines, but I will do my best to work through any requests.

If you'd like a copy of the BeebSCSI ROM (or the boot loader image to re-flash the device) - simply go to the GitHub and click on the 'releases' link. This will take you to a convenient zip file of just the bits you need.

BeebSCSI also has over 70 pages of user guides, hardware guides and technical documentation available including a 'quick start LUN image' that you can simply unzip onto an SD card to get going without having to format the first LUN from floppy using SuperForm (as you would have to with a real Winchester drive):

http://www.domesday86.com/?page_id=689

The quick-start guide (and zip file) are here:

http://www.domesday86.com/?page_id=400#Quick-start

If you find anything missing from the documentation or had problems following the guides, please report this on github too - if it confused you, it will probably do the same to others :)

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1024MAK
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Re: BeebSCSImini

Post by 1024MAK » Sat Dec 09, 2017 3:23 pm

Thanks Simon. A fair amount of bedtime reading there :mrgreen:

Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki‬ - for answers to many questions...

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danielj
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Re: BeebSCSImini

Post by danielj » Sat Dec 09, 2017 10:35 pm

Simon, Jason - just to say these are excellent. BeebSCSImini + Flash Floppy GoTEK and now I've been able to ditch the datacentre (sacrilege!), use native versions of all the filesystems and have precisely 0 compatibility problems :) Weeee! :)

d.

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Re: BeebSCSImini

Post by danielj » Sun Dec 10, 2017 6:24 pm

Attached is a quickstart zip with DOSPlus and GEM already installed. I may update to PANOS containing in due course!

d.
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IanB
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Re: BeebSCSImini

Post by IanB » Fri Dec 15, 2017 6:22 pm

Found a bug with more than one HD: (Tested on a Master 128)
After powering on the Master and beebSCSImini, if you type LOAD":0.XYZ" you get "not found" (assuming the file doesnt exist)
but if you type LOAD":1.XYZ" you get a disc error at sector 000000
If you then type *MOUNT 1 and then LOAD":1.XYZ" you get "not found" as expected.
If you then CTRL-BREAK the Master and type LOAD":1.XYZ" you still get "not found" so the firmware remembers the *MOUNT across a reset.

You don't get the disc error with a real second HD, always "not found".

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simoni
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Re: BeebSCSImini

Post by simoni » Fri Dec 15, 2017 7:49 pm

Found a bug with more than one HD
It's not clear from your description what you consider to be a bug?

The *MOUNT command in ADFS translates to a START command in SCSI-1. The *BYE command translates to a STOP. The START and STOP SCSI commands tell the SCSI controller to either make the LUN available or make the LUN unavailable. The Master's reset condition (i.e. CTRL-BREAK) doesn't result in any SCSI commands. Therefore the SCSI controller remains in a steady-state even though the Master resets (and the LUNs stay STARTed because nothing STOPped them). This is what the SCSI-1 specification states, and it's what BeebSCSI does :)

I don't believe this is a bug (unless it's a bug with your 'real' second HD). Preserving the LUN state across resets allows you to mount a drive and then SHIFT-BREAK into the drive to boot it (which is really useful).

If you don't *MOUNT a LUN it's STOPped and unavailable - the Master only ever mounts LUN 0 automatically (if configured to do so). If you issue a SCSI READ command (i.e. LOAD "something") to a stopped LUN, you will get a disc error because the LUN isn't available.

What is the 'real' hardware you are comparing against and what part of your description do you consider to be a bug?

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Re: BeebSCSImini

Post by IanB » Fri Dec 15, 2017 11:46 pm

The bug is that you get a disc error when trying to access HD1 after a power up (or *bye) unless you *mount it first
This doesn't happen with a pair of ST506 HDs connected to an Adaptec SCSI controller / host interface and I assumed you were aiming to emulate the behaviour of that standard hardware configuration.

I just tried doing a *BYE followed by a *.:1 on both my real HDs and the beebSCSI.
On the real Adaptec controller it gives a catalog, on BeebSCSI it gives a disc error.
It looks like the Adaptec ACB4000/4070 controller will auto restart a LUN if it gets a command targetted at that LUN.

I've used multiple Adaptec controlled drives on beebs since the late 80s and never seen this sort of disc error.

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simoni
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Re: BeebSCSImini

Post by simoni » Sat Dec 16, 2017 4:43 am

The bug is that you get a disc error when trying to access HD1 after a power up (or *bye) unless you *mount it first
This doesn't happen with a pair of ST506 HDs connected to an Adaptec SCSI controller / host interface and I assumed you were aiming to emulate the behaviour of that standard hardware configuration.
I was; but I had to follow the spec as I didn't have an original hard drive. I shall open a github issue on your behalf and also verify if this behaviour is the same on the VP415. Thanks for the info!

Edit: Issue track is here https://github.com/simoninns/BeebSCSI/issues/2

Edit2: Can you verify what error you get if you issue a command to a non-existent LUN on the real hardware? The error number should give me a clue as to which SCSI command (the START or READ) returns error in this case.

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marcusjambler
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Re: BeebSCSImini

Post by marcusjambler » Sat Dec 16, 2017 9:25 am

BeebSCSImini + Flash Floppy GoTEK and now I've been able to ditch the datacentre (sacrilege!), use native versions of all the filesystems and have precisely 0 compatibility problems
Hi Daniel. Is the Gotek relatively easy to set-up?

I'm keen to replicate.

Sorry for the off-topic request this probably needs moving to a different thread

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danielj
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Re: BeebSCSImini

Post by danielj » Sat Dec 16, 2017 9:39 am

Yup - very straight forward. This thread for the gotek: viewtopic.php?f=16&t=13718

d.

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Re: BeebSCSImini

Post by mph1708 » Sat Dec 16, 2017 5:48 pm

As the BeebSCSImini does not fit underneath the BBC Master M128 a suitable ribbon cable is required.
But the required cable is 34 way Male - Female IDC ribbon cable, which does not seem to be a common off the shelf item.
(Unlike the 34 way Female - Female variety which is in plentiful supply.)
Any suggestions for an economically priced source for one of these ?

Regards Mike

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danielj
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Re: BeebSCSImini

Post by danielj » Sat Dec 16, 2017 5:56 pm

The 34-way male cable mount IDC connector isn't a cheap part :( I've got 5 on order from China at the moment. The alternative is to swap the connector for a male one. I have a feeling it'll need mounting on the opposite side of the board though?

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Re: BeebSCSImini

Post by RobC » Sat Dec 16, 2017 6:06 pm

For the matchbox copros, I just took a 40-way female-female cable, cut off one end and added one of these instead:

https://www.ebay.co.uk/itm/252083808451

They sell the 34-way version with and without mounting lugs. I think the price was pretty competitive when I bought them but haven't checked in the last 12 months.

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simoni
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Re: BeebSCSImini

Post by simoni » Sat Dec 16, 2017 6:09 pm

This is really a question for Jason (the original board had a male IDC). As a 'hack-y-hack' though you could always just pop a dual row male header in there (if you have one with long-ish pins) and then plug the female IDC into that... can't see why it wouldn't work as long as you don't invert the cable :)

edit: RobC's idea is much less hacky and would prevent cable inversion.

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vanekp
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Re: BeebSCSImini

Post by vanekp » Sat Dec 16, 2017 6:11 pm

Would it not have been better to use a 90 deg for the power like this one :-
RightAnglePlug.png
As the straight one with a plug on it comes very close if not beyond the bottom of the BBC.
Peter.

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danielj
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Re: BeebSCSImini

Post by danielj » Sat Dec 16, 2017 6:12 pm

RobC wrote:For the matchbox copros, I just took a 40-way female-female cable, cut off one end and added one of these instead:

https://www.ebay.co.uk/itm/252083808451

They sell the 34-way version with and without mounting lugs. I think the price was pretty competitive when I bought them but haven't checked in the last 12 months.

Oooh, they're very reasonable in the great scheme of things!

d.

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danielj
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Re: BeebSCSImini

Post by danielj » Sat Dec 16, 2017 6:13 pm

Hehehe - everyone's a critic.

d.

IanB
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Re: BeebSCSImini

Post by IanB » Sun Dec 17, 2017 12:55 am

simoni wrote:Edit2: Can you verify what error you get if you issue a command to a non-existent LUN on the real hardware? The error number should give me a clue as to which SCSI command (the START or READ) returns error in this case.
Not sure how you want me to test that.
If you try to access a non existant drive from the command prompt you just get "not found". I also tried disconnecting drive 1 after bootup but the beeb just hung when trying to access it.
Do you have a test program that will send SCSI commands to a drive?

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simoni
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Re: BeebSCSImini

Post by simoni » Sun Dec 17, 2017 5:11 am

Not sure how you want me to test that.
I was just curious as to the response from the master if you have two LUNs (0 and 1) and you issue *MOUNT 2. What does the Master respond with?

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flynnjs
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Re: BeebSCSImini

Post by flynnjs » Sun Dec 17, 2017 8:23 am

If I do another batch then I'll revisit the power connector.
A few that I sent out did have right-angle connectors but I ran out.

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Re: BeebSCSImini

Post by IanB » Sun Dec 17, 2017 4:13 pm

simoni wrote:I was just curious as to the response from the master if you have two LUNs (0 and 1) and you issue *MOUNT 2. What does the Master respond with?
*MOUNT 0 mounts OK
*MOUNT 1 mounts OK
*MOUNT 2 "Not Found"
*MOUNT 3 "Not Found"

The Adaptec hardware only supports 2 LUNs so I'm not sure if ADFS is converting a SCSI error into the "Not found" message or is aborting any attempt to use more LUNs than the adapter supports.

Although Acorn reserved 4 slots for drives, I don't think there was any original hardware available that supported that configuration (i.e. a controller with 4 LUNs) but I patched ADFS back then to support multiple SCSI devices so you could either have two Adaptec cards with 2 Luns each or four separate embedded SCSI drives.

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simoni
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Re: BeebSCSImini

Post by simoni » Sun Dec 17, 2017 4:23 pm

The Adaptec hardware only supports 2 LUNs so I'm not sure if ADFS is converting a SCSI error into the "Not found" message or is aborting any attempt to use more LUNs than the adapter supports.
IIRC there's no way for ADFS to know how many LUNs are available, so it's probably a response to the SCSI error code coming back from the Adaptec board. I'll add this info to the github issue report and see if I can work out what's going on. Thanks for the report and the help!

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Re: BeebSCSImini

Post by stevei2791 » Thu Dec 21, 2017 1:26 pm

Hi

I finally got my cabling together and am trying to get the SCSImini working. I have 5v from the AUX port to the board and a 64gb SD card with nothing but the Quickstart directory with the two files. I have configured the master as per the instructions on the doomsday86 website but the hardware does not seem to be accessing the drive or returning any errors, it is as if the Master cannot see the board. *. and *mount 0 never return, the machine just sits waiting on a response.

I have checked the polarity of the cable and that seems fine, the documentation mentions an LED which does not appear to illuminate on my new board. Is there some other way to check that the board is visible to the Master?

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danielj
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Re: BeebSCSImini

Post by danielj » Thu Dec 21, 2017 2:03 pm

Is this a stock master, or have you got one of the multi-os type roms in there? Have you ever used it with an IDE CF adaptor?

d.

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Re: BeebSCSImini

Post by stevei2791 » Thu Dec 21, 2017 2:11 pm

It's not quite stock it has a multi-os from Mark so 3.20 and 3.50, both checked, unfortunately, both do not see the drive. I also have an external datacentre which is working so I suspect it is not the 1Mhz port.

I unplugged both versions of the IDE adfs, so only the adfs in slot 13 was inserted.

I have just ordered more male/female connectors to make another cable just to be sure it is not the cable and I'm just dumb, but those wont arrive until after the festivities.

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danielj
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Re: BeebSCSImini

Post by danielj » Thu Dec 21, 2017 2:14 pm

MultiOS has been patched so ADFS works with IDE, but that's removed the SCSI code from the ADFS ROMs. You'll need to get it the multios reprogrammed with the standard version of ADFS to use the BeebSCSI.

You won't be able to use the beebscsi at the same time as the external datacentre without adjusting the cable (I haven't looked into this in any detail) as the IDE/SCSI will clash :?

d.

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Re: BeebSCSImini

Post by danielj » Thu Dec 21, 2017 2:17 pm

(The alternative is to load the standard version of ADFS into sideways RAM and disable the one in slot 13, but you're still going to have a datacentre clash).

I'm thinking further on this - that will work, I think, with OS 3.2, but not 3.5 as some of slot 13 is needed for the OS, and it needs to be a specific number of slots away from the DFS ROM too.
d.

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Re: BeebSCSImini

Post by marcusjambler » Thu Dec 21, 2017 2:41 pm

Good to know... I have yet to try my new BeebSCSI board.
Looks like I wont be able to use it on my Retroclinic Master.
Can anyone confirm whether or not the IFEL MultiOS ROM has had the SCSI routines removed?

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