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Author Topic: SD card interface (Read 102608 times)

Offline Bagpuss22

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Re: SD card interface
« Reply #150 on: 2014.May.01. 21:12:36 »
AS always BP is interested  :ds_icon_cheesygrin:

Offline BruceTanner

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Re: SD card interface
« Reply #151 on: 2014.May.01. 22:28:35 »
Quote from: Saint
Also, would people want the card edge version, rather than my edge connector version?

I'm trying to think ahead as getting the PCB's made takes a little while.

Hi Saint, just wondering if you could do both versions with one PCB? Could the bottom row of holes of the edge connector actually be in the ”fingers” of a card edge? So don't fit the edge connector and you get a card edge, or fit the edge connector and ignore the card edge fingers? (You mentioned the possibility of making the PCB extend below the edge connector so it was at the same level as the base of the Enterprise...this might help.) Just an idea...I haven't looked at the dimensions or electrical connections!

Count me in for an edge connector one by the way...

B.

Offline Saint

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Re: SD card interface
« Reply #152 on: 2014.May.01. 22:50:09 »
I was just thinking about the idea of one PCB for both the edge connector and card edge... :)

I cant do it with a through hole edge connector, however its possible with a straddle mount type. This would then give a lay-flat type connection to the Enterprise rather than the vertical mount. I'll see what I can source in the way of edge connectors...

Offline CiH

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Re: SD card interface
« Reply #153 on: 2014.May.02. 00:09:18 »
Potentially interested here :-)

Offline BruceTanner

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Re: SD card interface
« Reply #154 on: 2014.May.02. 09:39:58 »
Quote from: Saint
This would then give a lay-flat type connection to the Enterprise rather than the vertical mount.
I didn't realise lay-flat was an option - I assumed you wanted a vertical one! In that case I wonder if it is possible to solder two conventional edge connectors back to back (I haven't tried it!)? Hopefully all the pins being soldered together would give enough mechanical strength and you could then just connect card edge to card edge.

Offline Saint

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Re: SD card interface
« Reply #155 on: 2014.May.03. 22:12:57 »
Vertical is the way I like it to save desk space, but I try and accommodate people's requirements. :) soldering two edge connectors together is a good idea, actually. I've had a look and reckon they would be plenty strong enough.

And a bit of an update. I've been busy converting my SPI driver code into Z80 machine code from C to work with Zozo's driver. First time I've actually done any proper Z80 coding! I still prefer 68000... ;)

I wish I knew Z80 a bit better though, as I'm sure I could reuse most of the existing SPI code from the cartridge device. But I feel it's much safer to convert my known working code. :)

Offline jltursan

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Re: SD card interface
« Reply #156 on: 2014.May.11. 20:39:57 »
Count with me for at least one PCB!. I really like the vertical solution :-)

Offline weirdocollector

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Re: SD card interface
« Reply #157 on: 2014.May.11. 21:21:00 »
Hi everybody from Italy !

Please count me in for an SD interface: my EP128 will be happy to get it !

Thanks a lot in advance.

Fabio.
(Milan-ITALY)

Offline Tricky

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Re: SD card interface
« Reply #158 on: 2014.May.11. 21:46:56 »
Hi Saint,

Please count me in for an SD interface - happy with either version.

Cheers

Tricky
Obsolescence Built in (to me)

Offline Saint

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Re: SD card interface
« Reply #159 on: 2014.May.12. 00:16:27 »
Good to see some more interest gathering. :) I've now written and tested the z80 assembler version of the SD card code and its working perfectly. The hardware has been tweaked a bit as well.

So now I'm working on the interface to EXDOS with Zozo's driver code. Getting close... :)

Offline Saint

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Re: SD card interface
« Reply #160 on: 2014.May.12. 10:21:50 »
I'm not sure if I mentioned, but this expansion includes SD card interface, 512KB RAM (which I can put at any address, so if you have an internal 64K, 512KB or 1MB expansion, I can map lower to give you additional RAM) and 512KB FLASH ROM. The FLASH ROM will be managed from an EXOS extension, allowing you to select ROMs from EXDOS and flash them into the card so you can have up to 32 ROMs installed.

Offline Z80System

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Re: SD card interface
« Reply #161 on: 2014.May.12. 10:31:51 »
Quote
which I can put at any address, so if you have an internal 64K, 512KB or 1MB expansion, I can map lower to give you additional RAM

Cannot it be standardized ? Not for all expansions in the universe, but at least among your expansions, or with (maybe consulted with Zozo) most of the expansions ?

So you mapped the the inside expansions somewhere, and by default mapping the SD card versions somewhere else, and the third kind again somewhere else ?

So users could combine them as their wish by default, without collision in the most of the cases ?
Z80 System

Offline Saint

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Re: SD card interface
« Reply #162 on: 2014.May.12. 11:05:00 »
Quote from: Z80System
Cannot it be standardized ? Not for all expansions in the universe, but at least among your expansions, or with (maybe consulted with Zozo) most of the expansions ?

So you mapped the the inside expansions somewhere, and by default mapping the SD card versions somewhere else, and the third kind again somewhere else ?

So users could combine them as their wish by default, without collision in the most of the cases ?
No.

The problem is, if you have an Enterprise 64, and would like to run 128 software, the RAM needs to include pages F8-FB. If you have an internal RAM expansion then this is covered, and the extra RAM could appear anywhere.

The address of the RAM is programmed into a GAL, so you would have to specify which version of the GAL you would like when ordering. Either one or Enterprise 64 to allow 128 compatibility, or one for extra RAM (which can be a set address for all machines which already have F8-FB mapped).

If I had thought about this more in the first place, I could have made this switchable by software, however as people either have an internal memory expansion or they don't, then two GAL's was easier.

Offline Z80System

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Re: SD card interface
« Reply #163 on: 2014.May.12. 11:20:57 »
Hmmm ... EP's hardware would support the segment address layout with a hw protocol or something ...

Different hw expansions would "register" their amount ... something central memory management hw would be good ...

At this time, it's too late to design such expandable hw memory management ... it seems (how you say) manual configurations is an absolutely need ...
« Last Edit: 2014.May.12. 11:25:29 by Z80System »
Z80 System

Offline Saint

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Re: SD card interface
« Reply #164 on: 2014.May.12. 11:25:51 »
Quote from: Z80System
At this time, it's too late to design such expandable hw memory management ... it seems (how you say) manual configurations is an absolutely need ...
I should add the only reason that the memory needs to be at F8-FB is because of "naughty" programs just assuming that these memory pages are available. If they had been written properly using the EXOS memory allocation, memory could be at any address and we would have no problem. :)