Where can I buy an XA-SK-FLASH slicecard

[zonedar]

Posted this query to the Questions site. Haven't gotten any replies, so I thought I'd try here. Apologies if I'm making a faux pas

I've found several references to an XA-SK-FLASH slice card that allows an SD Flash card to be acessed via an SPI or 4 bit interface (for example https://github.com/shanthinick/sc_sdcard ). However I've not been able find where I can purchase one or find schematics for one.

Is this a supported slice card and if so where can I purchase one or something similar? If it's not are there design files that I can get to fabricate one?

Thanks,

-Steve

[mon2]

Hi zonedar. The XA-SK-FLASH slicecard is an interesting find for the SD-Flash card use. The same slicecard is also referenced in the sc_flash IP (for testing the QUAD SPI interface) available on github.

https://github.com/xcore/sc_flash/blob/ ... doc/hw.rst

We invested a great deal of time and effort to reverse engineer the QUAD SPI flash IP which did not work for us as posted on github. Part of the research was to source the same requested details as yours - how to interface the QUAD SPI flash device as per the slicecard which did not appear to be public ? If there is an interest on such QUAD SPI port mappings, we can dig into our notes from the QUAD SPI project review. We did get the QUAD SPI interface to work correctly but it was a major rewrite to properly support the sourced Winbond and Spansion devices. Nevertheless a nice way to expand the noggin :) (One of my 2015 resolutions is to be more positive :)

Someone from XMOS needs to chime on the official position of this XA-SK-FLASH slicecard but we reported last year that the hardware setup for the QUAD SPI flash testing features a photo featuring a SDRAM slicecard (!!) (and not the actual XA-SK-FLASH slicecard). That is, very likely the photo was to be revised with photoshop once the XA-SK-FLASH slicecard was released.

See here for the wrong photo for the QUAD SPI flash project (shows SDRAM slicecard):

https://github.com/xcore/sc_flash/blob/ ... _setup.jpg

Noting your post, found the true photo of this mysterious XA-SK-FLASH slicecard here:

https://github.com/shanthinick/sc_sdcar ... kstart.rst

From the photo you can see 2 of the wide body 8 pin flash devices (similar to those we tested last year) + the SD card socket.

Reviewing the source code from your link:

https://github.com/shanthinick/sc_sdcar ... HostSPI.xc

and

https://github.com/shanthinick/sc_sdcar ... ost4Bit.xc


you can get an excellent start in understanding how the port pins are communicating with the SD-card interface. It will be best if XMOS supplies at least the schematic of this slicecard which appears to be MIA but not impossible to reverse engineer from the source code. We will ping our local XMOS engineer for assistance.

Pending the official support, you could consider to source the many low cost SD-Card boards on the market including the offshore versions from Aliexpress, etc. (most are < $ 5 USD) or Adafruit, Sparkfun, etc. Be sure to use a SD-card PCB with a 3.3 volt interface for the XMOS use !!

Post back if you have any questions on which board to source. Believe we have a similar connector board from a STM32F project board somewhere in the lab sourced from Shenzhen...

Since the XMOS ip already references the QUAD SPI and now SD-Card, the most practical route would be to shadow the official schematic for this XA-SK-FLASH slicecard.

In a pinch, we can review creating a slicecard with these interfaces but no firm ETA on such an effort.

Curious - which XMOS hardware are you using for this project ? StartKit ? SliceKit ? (which)

Hope this helps.

[zonedar]

mon2,

Thank you very much for the detailed reply. I feel a bit better that you too had problems finding this card. Not just me... ;)

I'm currently developing using a slice kit with GPIO, LCD, and SRAM slices. Ultimately I'd like to use an SD card to store the base images and 'sprites' for the LCD (leveraging the FAT file system examples) as well as user set configurations. I'd also like to boot from it (custom boot-loader?). This will make in-field updates easier.

These slices will be then rolled up into a custom board using either an L8-128 or L10-128. Having the SD slice card reduces development time and HW risk.

I'd certainly be interested in any info or notes that you have. You can contact me directly at zonedar (at sign) yahoo (dot) com, if you'd prefer not to do so on the forum.

If someone from XMOS could chime in with just schematics that would go a long way as it is possible I can get a slice card fabricated.

Thanks again!

-Steve

[mon2]

Steve,

1) opened a ticket requesting the official slice schematic for the XA-SK-FLASH slicecard. Hoping to receive a reply in the near future although we did not last year.

2) While waiting, please see the attached document created today. It looks to be correct but is missing the mappings for the dual flash SPI 8 pin devices shown in the posted github photo and also the 4 SMD LEDs. However, fairly confident the pinouts are as shown in the created document.

3) The source code mentions a few pull-up resistors but the comments do not agree with the many internet postings on this subject. For this reason, have noted the need for the referenced pull-ups on the CMD, DAT0..DAT3 lines.

Since we have not (yet) worked with this SD-Card interface, please review and use at your own risk. As we continue the review, the document will be revised. Let us know if you see any issues in the supplied details. Hope this helps.

Document version is 0.3 (Draft)
* Added details of source code which references the derived port pin mappings
* Added details of the QUAD SPI flash used in lab work from last year - confirmed working (last year) after interfacing to the noted pins (Note the pin & label typos in SliceKit hardware manual)
* More details to follow as time permits to enhance this document

[zonedar]

Mons,

Thanks a bunch. Can't tell you how much I appreciate your posting this for me. If I get the boot-loader and file system to run concurrently with the card I will post the code.

Thanks again!

-Steve