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1. 

   dinau
   Member

   Thank you for reply, gbulmer.

   I'm going to study general data rate expression.

   Regards,

   dinau

   Posted 2 years ago #
2. 

   dinau
   Member

   Hi, gbulmer
   Sorry for confusion about data rate expression.

   I modify correctly the data rate expression as follows:

   2G byte MicroSD card [Transcend], FAT16
   ( Using SdFatBench.pde and Olimexino-STM32(compatible Maple rev5 ) )

   Before: v02
   SD card read/write speed,
   [SPI clock], write, read
   [4.5MHz], 109kB/s, 168kB/s
   [ 9MHz ], 120kB/s, 192kB/s
   [18MHz ], 119kB/s, 192kB/s

   After: v03
   Improved SD card read/write speed,
   [SPI clock], write, read
   [4.5MHz], 153kB/s, 289kB/s
   [ 9MHz ], 176kB/s, 396kB/s
   [18MHz ], 192kB/s, 485kB/s

   Note: [kB/s]=[kilo byte per second]

   Regards,

   dinau

   Posted 2 years ago #
3. 

   gbulmer
   Moderator

   dinau - Thank you for clarifying the results. That is very much faster. Excellent work, well done.

   Maybe using DMA, and using the two SPI's, you could do RAID :-)

   Posted 2 years ago #
4. 

   dinau
   Member

   Hi, all

   I've tried to use polpla's Maple-SDFat-DMA,
   https://github.com/polpla/Maple-SDFat-DMA.

   I've imported only polpla's DMA part into my SdFatMaple-vld library because
   it has many examples easy to use.

   This information is very tentavive at this time.
   By modifying the DMA part of the library, it seems that read/write functions work.

   Using Maple rev5 compatible borad.
   SPI clock is 18MHz.
   SPI device is SPI2.
   2G byte MicroSD card.

   Results are as follows:

   [ SdFatBench.pde ]
   Type is FAT16
   File size 5 MB
   Starting write test. Please wait up to a minute
   Write 233.98 kB/sec

   Starting read test. Please wait up to a minute
   Read 877.19 kB/sec

   [CardInfo.pde]
   Initializing SD card...Wiring is correct and a card is present.

   Card type: SD2

   Volume type is FAT16

   Volume size (bytes): 2028896256
   Volume size (Kbytes): 1981344
   Volume size (Mbytes): 1934

   Files found on the card (name, date and size in bytes):
   BENCH.DAT 2013-02-10 09:11:16 5000000
   M3216-01.WAV 2013-02-10 09:11:16 16642410
   M3216-02.WAV 2013-02-10 09:11:16 21361538
   M3216-03.WAV 2013-02-10 09:11:16 16542764
   S441601.WAV 2013-02-10 09:11:16 66768191
   M44K16.WAV 2013-02-10 09:11:16 28914186
   CASIO.ZIP 2013-02-10 09:11:16 690

   Regards,

   dinau

   Posted 2 years ago #
5. 

   micah
   Member

   Hey again. I was just reading about some recent updates to the original SdFat library. Apparently with the Teensy 3.0 board people are getting more than 1.7 MBytes/s write speeds... wow!

   How hard would it be to update the Maple-SdFat port for this new release? Probably a lot has changed, but the Maple should be able to do anything the Teensy 3.0 can do, I'd think.

   Here's the discussion.

   Posted 2 years ago #

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