SDFileSystem with mutex for multiple SPI devices on the same SPI bus

Dependencies:   FATFileSystem

Dependents:   CC3000Nucleo401REProject

Fork of SDFileSystem by Mbed

Files at this revision

API Documentation at this revision

Comitter:
vpcola
Date:
Thu Oct 16 13:40:12 2014 +0000
Parent:
3:7b35d1709458
Commit message:
Added mutex for multiple devices on the same SPI bus

Changed in this revision

SDFileSystem.cpp Show annotated file Show diff for this revision Revisions of this file
SDFileSystem.h Show annotated file Show diff for this revision Revisions of this file
diff -r 7b35d1709458 -r f0bd1dfd6f62 SDFileSystem.cpp
--- a/SDFileSystem.cpp	Mon Mar 17 14:34:01 2014 +0000
+++ b/SDFileSystem.cpp	Thu Oct 16 13:40:12 2014 +0000
@@ -120,8 +120,8 @@
 
 #define SD_DBG             0
 
-SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
-    FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
+SDFileSystem::SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, Mutex & mutex, const char* name) :
+    FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs), _mutex(mutex) {
     _cs = 1;
 }
 
@@ -142,10 +142,12 @@
 int SDFileSystem::initialise_card() {
     // Set to 100kHz for initialisation, and clock card with cs = 1
     _spi.frequency(100000);
+    _mutex.lock();
     _cs = 1;
     for (int i = 0; i < 16; i++) {
         _spi.write(0xFF);
     }
+    _mutex.unlock();
     
     // send CMD0, should return with all zeros except IDLE STATE set (bit 0)
     if (_cmd(0, 0) != R1_IDLE_STATE) {
@@ -240,6 +242,7 @@
 
 // PRIVATE FUNCTIONS
 int SDFileSystem::_cmd(int cmd, int arg) {
+    _mutex.lock();
     _cs = 0;
     
     // send a command
@@ -256,14 +259,17 @@
         if (!(response & 0x80)) {
             _cs = 1;
             _spi.write(0xFF);
+            _mutex.unlock();
             return response;
         }
     }
     _cs = 1;
     _spi.write(0xFF);
+    _mutex.unlock();
     return -1; // timeout
 }
 int SDFileSystem::_cmdx(int cmd, int arg) {
+    _mutex.lock();
     _cs = 0;
     
     // send a command
@@ -283,11 +289,13 @@
     }
     _cs = 1;
     _spi.write(0xFF);
+    _mutex.unlock();
     return -1; // timeout
 }
 
 
 int SDFileSystem::_cmd58() {
+    _mutex.lock();
     _cs = 0;
     int arg = 0;
     
@@ -309,15 +317,18 @@
             ocr |= _spi.write(0xFF) << 0;
             _cs = 1;
             _spi.write(0xFF);
+            _mutex.unlock();
             return response;
         }
     }
     _cs = 1;
     _spi.write(0xFF);
+    _mutex.unlock();
     return -1; // timeout
 }
 
 int SDFileSystem::_cmd8() {
+    _mutex.lock();
     _cs = 0;
     
     // send a command
@@ -338,15 +349,18 @@
             }
             _cs = 1;
             _spi.write(0xFF);
+            _mutex.unlock();
             return response[0];
         }
     }
     _cs = 1;
     _spi.write(0xFF);
+    _mutex.unlock();
     return -1; // timeout
 }
 
 int SDFileSystem::_read(uint8_t *buffer, uint32_t length) {
+    _mutex.lock();
     _cs = 0;
     
     // read until start byte (0xFF)
@@ -361,10 +375,12 @@
     
     _cs = 1;
     _spi.write(0xFF);
+    _mutex.unlock();
     return 0;
 }
 
 int SDFileSystem::_write(const uint8_t*buffer, uint32_t length) {
+    _mutex.lock();
     _cs = 0;
     
     // indicate start of block
@@ -383,6 +399,7 @@
     if ((_spi.write(0xFF) & 0x1F) != 0x05) {
         _cs = 1;
         _spi.write(0xFF);
+        _mutex.unlock();
         return 1;
     }
     
@@ -391,6 +408,7 @@
     
     _cs = 1;
     _spi.write(0xFF);
+    _mutex.unlock();
     return 0;
 }
 
diff -r 7b35d1709458 -r f0bd1dfd6f62 SDFileSystem.h
--- a/SDFileSystem.h	Mon Mar 17 14:34:01 2014 +0000
+++ b/SDFileSystem.h	Thu Oct 16 13:40:12 2014 +0000
@@ -23,6 +23,7 @@
 #define MBED_SDFILESYSTEM_H
 
 #include "mbed.h"
+#include "rtos.h"
 #include "FATFileSystem.h"
 #include <stdint.h>
 
@@ -52,7 +53,7 @@
      * @param cs   DigitalOut pin used as SD Card chip select
      * @param name The name used to access the virtual filesystem
      */
-    SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name);
+    SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, Mutex & mutex, const char* name);
     
     virtual int disk_initialize();
     virtual int disk_status();
@@ -78,6 +79,7 @@
     
     SPI _spi;
     DigitalOut _cs;
+    Mutex & _mutex;
     int cdv;
 };