Issue 8 discussions...

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Silvester
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Re: Issue 8 discussions...

Postby Silvester » Sat May 04, 2019 9:43 am

Dave wrote:SC28L92... If a driver magically appears....
Ah, it would be some sort of sorcery to write a driver without the device/hardware :D
Dave wrote:Thanks for expressing interest, Silvester.
More than interest, I would be quite happy to write the driver (since no one else has come forward). The only problem is where is your reasonably priced source for SC28L92 ?

(The only thing I have to play with at the moment is R68561)


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Re: Issue 8 discussions...

Postby Dave » Sat May 04, 2019 6:59 pm

I'm working on the PCB a little today and will be ordering some prototypes. I have 2-3 people I'd like to send a hardware complete prototype to, so....

If I have Issue 8 work, that takes priority, but if I don't I'll get that PCB updated.

Couple of weeks?


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Re: Issue 8 discussions...

Postby Andrew » Mon May 06, 2019 10:25 pm

Hi Dave - will it be possible to connect the vDrive to the issue 8 motherboard ?
Last edited by Andrew on Tue May 07, 2019 9:29 am, edited 1 time in total.


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Re: Issue 8 discussions...

Postby Dave » Mon May 06, 2019 11:48 pm

Andrew wrote:Hi Dace - will it be possible to connect the vDrive to the issue 8 motherboard ?


Yes. Issue 8 supports microdrives, and implements the EC1 expansion port. Special attention will be given to RAW1 and RAW2 so they have the cleanest possible signal paths.

QLNET is also supported.


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Re: Issue 8 discussions...

Postby Andrew » Tue May 07, 2019 9:30 am

So if SGC, QL-SD and vDrive are supported, I'll be waiting for the release of issue 8 boards.


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Re: Issue 8 discussions...

Postby Silvester » Tue May 07, 2019 11:48 am

Dave wrote:I'm working on the PCB a little today and will be ordering some prototypes. I have 2-3 people I'd like to send a hardware complete prototype to, so....

If I have Issue 8 work, that takes priority, but if I don't I'll get that PCB updated.

Couple of weeks?

I've got a couple of SCN68681 (DIP40) on the way, so I'll have something to play with meantime :)

BTW did you consider priority encoding IPL0/2 & IPL1 interrupt on issue 8? As you may well know level 5 is unuseable (since if level 2 occurs you get level 7). The 3 byte receive buffer of the 68681 might struggle with latency of EXTINT against 16 FIFO of SC28C92(*). Since you are allowing RAM overlay (like GC & SGC) level 5 vector could be reassigned.

edit: * ...which might also suffer if long IPC dialogue shuts out interrupts too much.


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Re: Issue 8 discussions...

Postby Nasta » Tue May 07, 2019 1:30 pm

Silvester wrote:I've got a couple of SCN68681 (DIP40) on the way, so I'll have something to play with meantime :)

BTW did you consider priority encoding IPL0/2 & IPL1 interrupt on issue 8? As you may well know level 5 is unuseable (since if level 2 occurs you get level 7). The 3 byte receive buffer of the 68681 might struggle with latency of EXTINT against 16 FIFO of SC28C92(*). Since you are allowing RAM overlay (like GC & SGC) level 5 vector could be reassigned.

edit: * ...which might also suffer if long IPC dialogue shuts out interrupts too much.


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Re: Issue 8 discussions...

Postby tcat » Wed May 08, 2019 8:23 am

Hi,

This seems getting on a wider audience, I wish to ask a few questions, not being exactly a h/w insider, please bear with me.

[a] RE serials, are these UART compatible, I read earlier in the post about `6502'?
what would be connector terminals for SER1,2, BT plug, or D-Cannon style 9-pin (like US QL)? Or is it something around FTDI chip (Serial over USB)?

[b] RE MDV, I have not developed SMD skills, but I read that a new design of MDV head board available, if not SMD, I feel up to populating new boards myself, head assembly, mounting screws, ULA, head reseating, motor adjustment, the skils I have got.

[c] RE TK2 toolkit, I have on std 16K CARE ROM cartrige, is this ext. port availlable?

[d] RE casing (non h/w), will it fit in std black case, is Sinclair QL `casting die' available so we could get new plastic mouldings?

Many thanks for all the good work!
Tom


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Re: Issue 8 discussions...

Postby Pr0f » Wed May 08, 2019 11:49 am

Silvester wrote:
Dave wrote:I'm working on the PCB a little today and will be ordering some prototypes. I have 2-3 people I'd like to send a hardware complete prototype to, so....

If I have Issue 8 work, that takes priority, but if I don't I'll get that PCB updated.

Couple of weeks?

I've got a couple of SCN68681 (DIP40) on the way, so I'll have something to play with meantime :)

BTW did you consider priority encoding IPL0/2 & IPL1 interrupt on issue 8? As you may well know level 5 is unuseable (since if level 2 occurs you get level 7). The 3 byte receive buffer of the 68681 might struggle with latency of EXTINT against 16 FIFO of SC28C92(*). Since you are allowing RAM overlay (like GC & SGC) level 5 vector could be reassigned.

edit: * ...which might also suffer if long IPC dialogue shuts out interrupts too much.


Level 5 is only unusable in a stock BBQL because :

1) the autovector is unusable in current ROM
2) The hardware has no feature to block a level 2 interrupt, so although you can generate a level 5, it is likely to become a level 7 because of that other IPL line getting toggled by the ZX8302 or even worse - by the IPC chip which can theoretically control both IPL lines (only 2, as 68008 48 pin variety bonds 2 of the 3 together, giving 0 (none), 2, 5 and 7)

If Dave's design provides some additional gating around the interrupt area, then all things are possible :-)


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Re: Issue 8 discussions...

Postby Dave » Wed May 08, 2019 5:49 pm

tcat wrote:[a] RE serials, are these UART compatible, I read earlier in the post about `6502'?
what would be connector terminals for SER1,2, BT plug, or D-Cannon style 9-pin (like US QL)? Or is it something around FTDI chip (Serial over USB)?

Maybe you're thinking 68681? There is a separate project to get a half-way modern UART working on the QL, with driver support. I

We're using 9 pin D-SUB connectors, like on the US and German QLs. Two reasons: the 631 BT style connectors are not available, and they are also an abomination. The serial levewl conversion hardware is all new and based on the ADM208EAR 5V device instead of an MC1488/1489 pair - those require +12V and -12V and needlessly complicate the power supply design. One goal of this board is to have it run off a single DC supply as there is a chronic shortage of QL power supplies. Anything we can do to free up even a few will help greatly.

tcat wrote:[b] RE MDV, I have not developed SMD skills, but I read that a new design of MDV head board available, if not SMD, I feel up to populating new boards myself, head assembly, mounting screws, ULA, head reseating, motor adjustment, the skills I have got.

I designed a replacement microdrive board that was 4-layer and mostly SMD. It did provide cleaner signal paths. It took some time to make a jig so the heads could be absolutely properly aligned, and this turned out to be the only critical part of the process. That is not something the average person would be able to do at home. As there are no new heads, it involves non-destructively recovering the heads from low-mileage microdrive units, removing the ULA, then porting those onto the new board and remounting/aligning it onto the original frame. It is not for the faint of heart.

I will be porting that PCB design to my current PCB design software later in the year and will make 15-20 available. I have already disassembled that many microdrives, but got completely sidetracked when I had my heart attack.

tcat wrote:[c] RE TK2 toolkit, I have on std 16K CARE ROM cartrige, is this ext. port availlable?

The Issue 8 has a standard ROM port, with one minor change. The plastic molding is black. I plan to discontinue the ROM port after Issue 8 as the image can be saved in flash and relocated. I found the connectors to be very difficult to source, and quite expensive at £5/00 a piece. Therefore, I will be offering it as a built time option - if you don't want it, your Issue 8 board will be £5 cheaper.

We've done another small yet big change with the ROM port, but we're not ready to discuss it yet. It doesn't affect compatibility but improves flexibility of expansion options.

tcat wrote:[d] RE casing (non h/w), will it fit in std black case, is Sinclair QL `casting die' available so we could get new plastic mouldings?

The Issue 8 fits in a standard QL case.

Currently, you'd have a QL that is broken or in need of upgrade. You'd open it and remove the microdrives and QL PCB. You'd transfer the 8301, 8302 and 8049 across to the new board. You'd take the supplied template and mark up the back of your QL case, then alter the slots where Ser1, Ser2, Joy1 and Joy2 are to match a German QL.

On the current board, we implement in order the ROM port 100% compatible, Joy2, Joy1 in Kempston pinout (now protected by diodes), Ser2 and Ser1, reset in the UHF hole, RGB 8 pin DIN (signals now buffered and protected), power in, QL net 2 and 1, the reset button location is now a proper on/off rocker switch. Power and microdrive LEDs match. The EC1 microdrive expansion connector is implemented. We're implementing QIMI on board, and will include either an Atari 9-pin D-SUB or a Microsoft Inport (9 pin mini-DIN) connector in a new location. This will likely be beside the power socket (mini-DIN) or by the RGB port (D-SUB). We will mount it so if you do not want to use it you do not need to expose the miniDIN connector, or the D-SUB can be supplied loose. If you do not want the QIMI port installed as a build time option, we'll knock a bit off the price.

The J1 DIN41612 connector is implemented, but some signals have been changed. We've converted some to ground, and others to extend the address bus. Also, the 68SEC000 does not implement the 6800-style interrupt system, so we made useful changes there. The only card we're aware of that used the 6800 interrupt system is the QEPIII programmer - that will not work with Issue 8.

Super Gold Cards, Gold Cards, Trump Cards, Floppy/IDE cards will work. QL-SD will work, but you might need to get a slightly longer ribbon cable, depending on how long yours is. If this proves to be a problem, we'll make one available. There will be a LOT less RF noise inside the QL with an Issue 8 board, so long cable runs will not pick up noise like they do in Issue 5 or 7.



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