New SdFat library (with and without DMA)
The code in the official repo from Bill Greyman has now the support for the libmaple based core (stm32duino) integrated in it. So no need to download it from my repo any more.
Official SD-Fat library repository:
https://github.com/greiman/SdFat
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UPDATE TO THIS WARNING. SHOULD BE SOLVED IN THE LATEST REPO. If you have problems using pin 7 for CS, make sure you are in sync with Roger’s master STM32Duino repo.
WARNING!!
I was just testing an SD card with one of the sketches, and noticed that you CAN NOT use pin 7 in the Maple MiniMaple MiniОтладочные и вычислительные платы…8MHz petertumler Thu Sep 24, 2015 10:58 am Hi, I’m trying to underclock a STM32F103 ( Maple Mini ) to 48MHz (for energy efficiency reasons). According to the datasheet .. The full…Underclocking STM32F103 to 48MHz (the STM32F103STM32F103Микроконтроллеры и процессоры…19.html . ag123 Sat Apr 28, 2018 5:54 pm come to think of it blue pill / maple mini ( stm32f103 ) is an *ideal* keyboard controller, the scanning can be done with assistance of sh…[SOLVED] generic blue pill clone as USB keyboard native SS pin for spi1) for CS. I have not looked at how the library manages CS and how that pin is setup in out SPI library, but I guess there is a conflict in the pin mode. So the work around at the moment is to use a different pin for CS.
– Updated 06/04/2015-
– New update on 07/10/2015 – Small code changes to the library and specially to the SPI library, which should go to Roger’s master repo soon.
So as I posted before in the forum, I modified the latest SdFat library from Greiman.
I had submitted him changes for a previous version, but had issues. Now all the issues seem to be corrected in my latest version.
It is available here:
https://github.com/victorpv/SdFat
It seems to work fine for me for the few examples I have tested.
If you want the best performance for large transfers, can use DMA mode.
DMA would be advantageous for large transfers, but doesn’t help at all, and may even have a penalty, if you are just reading a few bytes to a log and things like that. Now if you transfer images or mp3 files from the sdcard, DMA can improve performance greatly, anything involving big blocks at once.
DMA can be enabled or disabled editing SdSpiSTM32F1.cpp, there is one #define line:
/** Use STM32STM32Микроконтроллеры и процессоры…Map magic glue code, ethernet compiles, just WARNING: library LwIP claims to run on [ stm32 ] architecture(s) and may be incompatible with your current board which runs on [STM32]…[STM32GENERIC] F429i Discovery DMAC if nonzero */
#define USE_STM32F1STM32F1Микроконтроллеры и процессоры…w I am not able to compile. Error message: “C:\arduino-1.6.12\hardware\Arduino_STM32\ STM32F1 \cores\maple/boards.h:39:25: fatal error: board/board.h: No such file or directory” I…Value Line Discovery Board _DMAC 1
Comment that line or change the 1 for 0, and DMA transfers will not be used.
RECOMMENDATIONS FOR SPEED:
Use DMA mode.
Set a bigger buffer, ideally 4KB
Read speeds without DMA, 4KB buffer:
read speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
676.29,8189,5927,6056
676.38,7467,5927,6054
676.38,7468,5927,6054
676.38,7469,5926,6054
676.38,7472,5926,6054
