Diff: PRAMFileSystem.cpp

Revision:

0:475e05403ad8

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PRAMFileSystem.cpp	Mon Nov 12 15:36:45 2012 +0000
@@ -0,0 +1,123 @@
+/*
+ * Memory File System Library, for SPI PRAM NP8P128A13 (Micron)
+ * Copyright (c) 2012 Hiroshi Suga
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+
+#include "mbed.h"
+#include "PRAMFileSystem.h"
+
+PRAMFileSystem::PRAMFileSystem (PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name) :
+  FATFileSystem(name), _spi(mosi, miso, sclk), _cs(cs) {
+    _cs = 1;
+}
+
+int PRAMFileSystem::_init () {
+    int i;
+
+    _spi.frequency(16000000);
+    _cs = 1;
+    wait_ms(10);
+
+    _cs = 0;
+    _spi.write(CMD_RDID);
+    i = _spi.write(0);
+    i = (_spi.write(0) << 8) | _spi.write(0);
+    _cs = 1;
+    if (i == 0 || i == 0xffff) {
+        return -1;
+    }
+ 
+    return 0;
+}
+
+int PRAMFileSystem::disk_initialize() {
+    if (_init()) {
+        return 1;
+    }
+    _sectors = 128 * 1024 * 1024 / 8 / 512;
+    return 0;
+}
+
+int PRAMFileSystem::disk_write(const char *buffer, int block_number) {
+    int i, addr;
+    
+    addr = block_number * 512;
+    for (i = 0; i < 512; i += 64) {
+        _write(addr + i, &buffer[i], 64);    
+    }
+    return 0;    
+}
+
+int PRAMFileSystem::disk_read(char *buffer, int block_number) {        
+    int i, addr;
+    
+    addr = block_number * 512;
+    for (i = 0; i < 512; i += 64) {
+        _read(addr + i, &buffer[i], 64);    
+    }
+    return 0;
+}
+
+int PRAMFileSystem::disk_status() { return 0; }
+int PRAMFileSystem::disk_sync() { return 0; }
+int PRAMFileSystem::disk_sectors() { return _sectors; }
+
+
+int PRAMFileSystem::_status () {
+    int r;
+
+    _cs = 0;
+    _spi.write(CMD_RDSR);
+    r = _spi.write(0);
+    _cs = 1;
+    return r;
+}
+
+int PRAMFileSystem::_write (int addr, const char *buf, int len) {
+    int i;
+
+    while (_status() & 1) {
+        // write in progress
+        wait_us(1);
+    }
+
+    _cs = 0;
+    _spi.write(CMD_WREN);
+    _cs = 1;
+    wait_us(1);
+
+    _cs = 0;
+    _spi.write(CMD_PP_BA);
+    _spi.write((addr >> 16) & 0xff);
+    _spi.write((addr >> 8) & 0xff);
+    _spi.write(addr & 0xff);
+
+    len = len - (addr & 0x3f);
+    for (i = 0; i < len; i ++) {
+        _spi.write(buf[i]);
+    }
+    _cs = 1;
+    return i;
+}
+
+int PRAMFileSystem::_read (int addr, char *buf, int len) {
+    int i;
+
+    while (_status() & 1) {
+        // write in progress
+        wait_us(1);
+    }
+
+    _cs = 0;
+    _spi.write(CMD_READ);
+    _spi.write((addr >> 16) & 0xff);
+    _spi.write((addr >> 8) & 0xff);
+    _spi.write(addr & 0xff);
+
+    for (i = 0; i < len; i ++) {
+        buf[i] = _spi.write(0);
+    }
+    _cs = 1;
+    return i;
+}