mi mi / SDFileSystemDMA Featured

first 2016/02 SDFileSystemDMA inherited from Official SDFileSystem.

Dependents:   SDFileSystemDMA-test DmdFullRGB_0_1

Fork of SDFileSystemDMA by mi mi

SDFileSystemDMA is enhanced SDFileSystem library for STM32 micros by using DMA functionality.
Max read transfer rate reaches over 2MByte/sec at 24MHz SPI clock if enough read buffer size is set.
Even though minimum read buffer size (512Byte) is set, read transfer rate will reach over 1MByte/sec at 24MHz SPI Clock.
( but depends on the ability of each SD card)

Test program is here.
https://developer.mbed.org/users/mimi3/code/SDFileSystemDMA-test/

/media/uploads/mimi3/sdfilesystemdma-speed-test3-read-buffer-512byte.png

/media/uploads/mimi3/sdfilesystemdma-speed-test-buffer-vs-spi-clock-nucleo-f411re-96mhz.png

Supported SPI port is shown below table.

(v): Verified. It works well.
(w): Probably it will work well. (not tested)
(c): Only compiled. (not tested)
(f): Over flash.
(r): Only read mode. (when _FS_READONLY==1)
(u) Under construction
(z): Dose not work.

Caution

If your board has SRAM less than or equal to 8KB, the buffer size must be set to 512 Bytes.

Supported Boards:
Cortex-M0

BoardSRAMSPI1SPI2SPI3
NUCLEO-F030R88KB(v)
DISCO-F051R88KB(w)
NUCLEO-F031K64KB(f)
NUCLEO-F042K66KB(r)
NUCLEO-F070RB16KB(w)
NUCLEO-F072RB16KB(w)
NUCLEO-F091RC32KB(c)

Cortex-L0

BoardSRAMSPI1SPI2SPI3
DISCO-L053C88KB(c)
NUCLEO-L053R88KB(c)
NUCLEO-L073RZ20KB(c)

Cortex-M3

BoardSRAMSPI1SPI2SPI3
DISCO-F100RB8KB(v)(v)-
BLUEPILL-F103CB20KB(w)(w)-
NUCLEO-F103RB20KB(v)(v)-
NUCLEO-L152RE80KB(v)(w)-
MOTE-L152RC32KB(w)(w)-

Cortex-M4
F3

BoardSRAMSPI1SPI2SPI3
DISCO-F303VC40KB-(v)(v)
NUCLEO-F303RE64KB(w)(w)(w)
NUCLEO-F302R816KB--(c)
NUCLEO-F303K812KB(c)--
DISCO-F334C812KB(c)--
NUCLEO-F334R812KB(c)--

F4

BoardSPI1SPI2SPI3
ELMO-F411RE(w)-(w)
MTS-MDOT-F411RE(u)-(u)
MTS-DRAGONFLY-F411RE(w)-(w)
NUCLEO-F411RE(v)-(v)
NUCLEO-F401RE(w)-(w)
MTS-MDOT-F405RG(u)-(u)
NUCLEO-F410RB(c)-(c)
NUCLEO-F446RE(c)-(c)
NUCLEO-F429ZI(c)-(c)
B96B-F446VE(c)-(c)
NUCLEO-F446ZE(c)-(c)
DISCO-F429ZI(u)-(u)
DISCO-F469NI(c)-(c)

Information

This library is set to use "short file name" in SDFileSystemDMA/FATFileSystem/ChaN/ffconf.h . ( _USE_LFN=0)
You can change this option to _USE_LFN=1 .

Diff: SDFileSystemDMA.cpp

Revision:
29:5375c51d0cfc
Parent:
21:41129109d6ab
Child:
37:844a602e6edf
--- a/SDFileSystemDMA.cpp	Sat Feb 20 13:44:01 2016 +0900
+++ b/SDFileSystemDMA.cpp	Tue Feb 23 21:21:07 2016 +0900
@@ -251,17 +251,35 @@
     if (!_is_initialized) {
         return -1;
     }
-    
-    for (uint32_t b = block_number; b < block_number + count; b++) {
-        // set read address for single block (CMD17)
-        if (_cmd(17, b * cdv) != 0) {
-            return 1;
-        }
-        
-        // receive the data
-        _read(buffer, 512);
-        buffer += 512;
-    }
+   
+	if(count==1){
+		//for (uint32_t b = block_number; b < block_number + count; b++) {
+			// set read address for single block (CMD17)
+			if (_cmd(17, block_number * cdv) != 0) {
+				return 1;
+			}
+
+			// receive the data
+			_read(buffer, 512);
+			buffer += 512;
+		//}
+	} else {
+		int retry=4;
+		while(retry--){
+			if (_cmd(18, block_number * cdv ) == 0) {	/* READ_MULTIPLE_BLOCK */
+				do {
+					_read(buffer, 512);
+					buffer += 512;
+				} while (--count);
+				_cmd(12, 0);				/* STOP_TRANSMISSION */
+				break;
+			} 
+			else {
+				//error("\nCMD18: disk_read()");
+			}
+		}
+		if(!retry) return 1;
+	}
 
     return 0;
 }