Has any user created a SD memory shield/library from the Arduino to the Maple?

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Has any user created a SD memory shield/library from the Arduino to the Maple?

(149 posts) (39 voices)

Started 5 years ago by leaflabsandy
Latest reply from feurig

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polpla
Member

Hi!

I have very good news! I just had great success implementing DMA into the existing library and getting an amazing increase of speed reading files. I haven't implemented DMA for writing yet but, as far as reading is concerned, this is multiplying by 6-7 the previous speed!!

I am very happy to share this with you people. Hopefully someone will benefit from this. Let me know if you want the code for now.

Mbolivar – I have never done a pull request (as a matter of fact, I don't know what that is really). If you tell me how to do it I'll be happy to contribute my code so that the library is available with the new improvements as soon as I finish implementing the writing part.

This is great!!

Posted 4 years ago #
polpla
Member

I want to add some acknowledgments here (sorry I forgot).

BIG THANKS TO ROBODUDE666 for sharing his expertise in DMA!

See thread here: http://forums.leaflabs.com/topic.php?id=1075

Posted 4 years ago #
mpaulin
Member

Hi Popla: Well done! Can you post the code for us to download?

Posted 4 years ago #
gbulmer
Moderator

polpa Well done!

... as far as reading is concerned, this is multiplying by 6-7 the previous speed!! ...

So how fast is that in KB/second?

Posted 4 years ago #
mbolivar
LeafLabs

polpla,

A "pull request" is a piece of GitHub machinery that lets anybody propose that some code get added into a repository that they don't have direct control over. We really like them because they've got nice code review interfaces.

Here are some existing pull requests for libmaple:

https://github.com/leaflabs/libmaple/pull/33
https://github.com/leaflabs/libmaple/pull/27

If you click those links, you'll see that the pull request interface includes the commits which people want merged into libmaple, a comment thread about them, and a nice diff view of the changes implied by all the commits.

GitHub has fantastic documentation if you want to learn more; see these notes for more information:

http://leaflabs.com/docs/libmaple/contributing.html

I also think that, based on the other thread you've linked to, you and robodude have got the makings of a stellar tutorial + example code on using DMA with SPI. Adding this to the wiki page on DMA would be an awesome way to contribute (without having to learn Git):

http://wiki.leaflabs.com/index.php?title=DMA

Currently, that page just has notes I wrote for myself while writing dma.h. Lots of people would appreciate more material there; we get threads asking how to use DMA all the time, but the docs are still pretty unfriendly to beginners.

Posted 4 years ago #
polpla
Member

Thanks guys!

mpaulin - I am polishing the code right now (there are a some bugs that generate errors every once in a while). Hopefully, a couple more days of work will deal with that. I'll keep you posted. Also, I would like to include the changes in the write processes.

gbulmer - I just tested and I am getting 1700KB/s approx.

mbolivar – I am going to take you up in both things, pull request to update the sdCard library and little SPI+DMA tutorial. It may take me a while since I have to focus on finishing the project I am working on but I'll try my best. I may start doing the tutorial but I will definitely try github for the library update eventually.

Posted 4 years ago #
gbulmer
Moderator

polpa

I just tested and I am getting 1700KB/s approx.

1.7MByte/second? Wow

I'd be okay with half that throughput :-)
Well done.

Is this speed up mostly due to DMA, or did you implement some other changes too?

Posted 4 years ago #
mbolivar
LeafLabs

polpla - Thanks, and happy hacking!

Posted 4 years ago #
polpla
Member

The increase of speed is mostly due to DMA. However, there is a couple changes you can do to the current library to make it a little bit faster with no DMA.

The thing that helps the most is to replace the functions for sending and receiving data over SPI. The library is using the deprecated function send (from HardwareSPI); if you replace it by write in spiSend and for transfer in apiRec you will see an increase in performance (if I remember correctly between 20% and 40% faster).

Also unwinding the loop that sends the argument in cardCommand function helped a bit (way less but it takes a second to do).

Finally, something that helps (specially for initialization is to make the class inherit from HardwareSPI instead of holding an HardwareSPI object. That is a little bit more involved but worth it (ti makes initialization 8% faster and the rest of the code between 1-2% faster).

Hope it helps!

Posted 4 years ago #
gbulmer
Moderator

polpla - thanks for the feedback.

1.7MByst/s is equivalent to about 40 instructions/byte.
I guess that speed is feasible in software if it went straight to the hardware and looped across abuffer, polling registers and moving bytes directly. The factor of 6-7x slower was suffering a load of library layers.

DMA access is saving that overhead, and it is almost 'free' CPU cycles, so a better solution :-)

Posted 4 years ago #
robertcook
Member

I'm porting over a program that uses and SD card from Arduino. I'm not using SDFat there, so it's all fairly new.

Because of my unfamiliarity with Maple, I'm incorrectly following procedures. I downloaded the latest build of Maple SDFat from Google Code. I put the library files in the 'libraries' subdirectory of my "MapleIDE" directory.

When I try compiling even the simplest examples, I get an error while compiling the library:

/Users/robert/Documents/MapleIDE/libraries/SdFat/SdBaseFile.h:26: fatal error: avr/pgmspace.h: No such file or directory
compilation terminated.

Given that this is not an AVR processor, this seems suspicious.

Probably a simple fix, but I figured if I'm stymied for this for more than 10 minutes, its a sign that something may have to be documented someplace.

Posted 4 years ago #
robertcook
Member

OK. I appear to have been using the wrong SDFat -- the original Arduino version.

I now have the one from Google Code, but the library is compiling with an error (in red) that I can't view:

/Users/robert/Documents/MapleIDE/libraries/mapleSDfat/Sd2Card.cpp: In member function 'uint8_t Sd2Card::readData(uint32_t, uint16_t, uint16_t, uint8_t*)':
/Users/robert/Documents/MapleIDE/libraries/mapleSDfat/SdFile.cpp: In member function 'uint8_t SdFile::rmRfStar()':

There is a thread from a year ago that suggests library errors are not shown in the MapleIDE:
http://forums.leaflabs.com/topic.php?id=117

Is this still true? If so, what's the workaround?

Also, I found the documentation on "SerialUSB" to be at the very least inconsistent:
http://leaflabs.com/docs/lang/api/serialusb.html?highlight=usb%20serial

The Library section refers to the class as "USBSerial", which threw me for a couple of minutes until I realized it was just in error.

Posted 4 years ago #
sononum
Member

Hi robertcook,

I figured out that this are just two warnings, I had the example to compile and upload successfully - take care you are using the right spi and note that the ssd /CS - pin is hard coded with magic numbers in the library (pin 10) I had to change line 191, 103 & 109 in Sd2Card.cpp

Posted 4 years ago #
robertcook
Member

Thanks sononum. I managed to get it all to work.

I'm getting about 50Kbytes/sec (and need about 3X that), so looking forward to the efficiency gains that popla is working on.

Posted 4 years ago #
erg144
Member

I'm just getting back into working with the maple and need to read/write to an sd card. I followed the steps carefully - download the latest from GIT, expend into the libraries directory, restart the IDE.

When I try and compile any of the examples I get numerous errors: Seems like i need to download some additional items. did a file search for PGM_P and I can only find the usage of them, not the definition.

C:\development\maple-ide-0.0.12-windowsxp32\libraries\SdFat/SdFatUtil.h:57: error: variable or field 'SerialPrint_P' declared void

C:\development\maple-ide-0.0.12-windowsxp32\libraries\SdFat/SdFatUtil.h:57: error: 'PGM_P' was not declared in this scope

C:\development\maple-ide-0.0.12-windowsxp32\libraries\SdFat/SdFatUtil.h:66: error: variable or field 'SerialPrintln_P' declared void

C:\development\maple-ide-0.0.12-windowsxp32\libraries\SdFat/SdFatUtil.h:66: error: 'PGM_P' was not declared in this scope

In function 'void error_P(const char*)':
error: 'PSTR' was not declared in this scope In function 'void setup()':

Posted 4 years ago #

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