Diff: USBDevice/USBMSD/AT45.cpp

Revision:

2:27a7e7f8d399

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBDevice/USBMSD/AT45.cpp	Fri Nov 11 15:22:53 2011 +0000
@@ -0,0 +1,829 @@
+#include "AT45.h"
+#include "mbed.h"
+
+/* mbed Library - AT45
+ * (c)2007, cstyles
+ */
+
+
+
+/* 
+ * Constructor
+ */
+
+AT45::AT45(PinName mosi, PinName miso, PinName clk, PinName ncs) 
+    : _spi(mosi, miso, clk), _ncs(ncs) {    
+    
+    _pages = -1;       // number of pages
+    _pagesize = -1;    // size of pages 256/264, 512/528, 1024/1056
+    _devicesize = -1;  // In bytes
+
+    _buffer1address = -1;  // page address in buffer 1
+    _buffer2address = -1;  // page address in buffer 2
+    _lru = -1;             // leas recently used buffer (for eviction)
+
+    _reset();          // Populate all this stuff
+
+}
+
+    
+    
+    
+
+/* 
+ * This is the reset function of the constructor.
+ * Interrogate the part and set up some variables.
+ */
+
+void AT45::_reset() {
+    int _id = 0;
+    int _status = 0;
+
+    _spi.format(8,0);
+    _spi.frequency(5000000);
+
+    _id = id();
+    _status = status();
+  
+    if ( (_id & 0x1f) == 0x2) { // 1Mbit
+        _devicesize = 131072; // size in bytes
+        _pages = 512;         // number of pages
+        _blocks = 256;        // Number of 512 byte blocks
+        if (_status & 0x1) {
+            _pagesize = 256;}
+        else {
+            _pagesize = 264;}    
+    }
+
+    else if ( (_id & 0x1f) == 0x3) { // 2M 
+        _devicesize = 262144; // Size in bytes
+        _pages = 1024;        // Number of pages
+        _blocks = 512;        // Number of 512 byte blocks
+        if (_status & 0x1) {
+            _pagesize = 256;}
+        else {
+            _pagesize = 264;}    
+    }
+
+    else if ( (_id & 0x1f) == 0x4) { // 4M 
+        _devicesize = 524288;
+        _pages = 2048;
+        _blocks = 1024;        // Number of 512 byte blocks
+        if (_status & 0x1) {
+            _pagesize = 256;}
+        else {
+            _pagesize = 264;}    
+    }
+
+    else if ( (_id & 0x1f) == 0x5) { // 8M 
+        _devicesize = 1048576;
+        _pages = 4096;
+        _blocks = 2048;        // Number of 512 byte blocks
+        if (_status & 0x1) {
+            _pagesize = 256;}
+        else {
+            _pagesize = 264;}    
+    }
+
+    else if ( (_id & 0x1f) == 0x6) { // 16M 
+        _devicesize = 2097152;
+        _pages = 4096;
+        _blocks = 4096;        // Number of 512 byte blocks
+        if (_status & 0x1) {
+            _pagesize = 512;}
+        else {
+            _pagesize = 528;}
+    }
+    
+    else if ( (_id & 0x1f) == 0x7) { // 32M 
+        _devicesize = 4194304;
+        _pages = 8192;
+        _blocks = 8192;        // Number of 512 byte blocks
+        if (_status & 0x1) {
+            _pagesize = 512;}
+        else {
+            _pagesize = 528;}
+    }
+    
+    else if ( (_id & 0x1f) == 0x8) { // 64M 
+        _devicesize = 8388608;
+        _pages = 8192;
+        _blocks = 16384;
+        if (_status & 0x1) {
+            _pagesize = 1024;}
+        else {
+            _pagesize = 1056;}
+    }
+    
+    else {
+        _devicesize = -1;
+        _pages = -1;
+        _pagesize = -1;
+    }
+}
+     
+
+
+
+
+/* 
+ * Select pulls nCS low, but also ensure SPI channel is formatted
+ * This is so that another device sharing the same SPI pins
+ * doenst leave it in an unknown state
+ */
+
+void AT45::_select() {
+    // ensure that the SPI port is set up correctly still
+    // This allows SPI channel sharing
+    _spi.format(8,0);
+    _spi.frequency(5000000);
+    _ncs = 0;    
+}
+    
+
+
+
+
+/* 
+ * Deselect simply returns nCS to high
+ */
+void AT45::_deselect() {
+    _ncs = 1;
+}
+            
+
+
+
+
+/* 
+ * Work out the page address
+ * If we have a 2^N page size, it is just the top N bits
+ * If we have non-2^N, we use the shifted address
+ */
+
+int AT45::_getpaddr(int address) {
+
+    int paddr;
+
+    if (_pagesize == 256) {                 
+        paddr = address & 0xffffff00;}    
+    else if (_pagesize == 264) {                 
+        paddr = (address << 1) & 0xfffffe00;}
+    else if (_pagesize == 512) {                 
+        paddr = address & 0xfffffe00;}
+    else if (_pagesize == 528 ) {           
+       paddr = (address << 1) & 0xfffffc00;}
+    else if (_pagesize == 1024) {                 
+       paddr = address & 0xfffffc00;}
+    else if (_pagesize == 1056 ) {           
+        paddr = (address << 1) & 0xfffff800;}
+    else {
+        paddr = 0xdeadbeef;}
+    
+    return (paddr);
+ 
+}
+
+
+
+
+
+/*
+ * Clean the buffer address. This is the 8/9/10 LSBs
+ */
+
+int AT45::_getbaddr(int address) {
+
+    int baddr;
+
+    if ((_pagesize == 256) || (_pagesize == 264 )) {
+        baddr = address & 0xff;}
+    else if ((_pagesize == 512) || (_pagesize == 528 )) {
+        baddr = address & 0x1ff;}
+    else if ((_pagesize == 1024) || (_pagesize == 1056 )) {
+        baddr = address & 0x3ff;}
+    else {
+        baddr = 0xcafebabe;}
+
+    return (baddr);
+}
+
+
+
+
+
+/*
+ * Return the Id of the part
+ */
+  
+int AT45::id() { 
+    int id = 0;
+    _select();
+    _spi.write(0x9f);
+    id = (_spi.write(0x00) << 8);
+    id |= _spi.write(0x00);
+    _deselect();            
+    return id; 
+}
+
+
+
+
+
+/*
+ * return the Status
+ */
+
+int AT45::status() { 
+    int status = 0;
+    _select();
+    _spi.write(0xd7);
+    status = (_spi.write(0x00) << 8 );
+    status |= _spi.write(0x00);
+    _deselect();            
+    return status; 
+}
+
+
+
+
+
+/*
+ * Erase the entire chip
+ */
+
+void AT45::erase() { 
+
+    _pollbusy(); // make sure flash isnt already in busy.
+
+    // There are errata on this. For now, do itthe long way :-(
+    _select();
+    // 4 byte command sequence
+    _spi.write(0xc7);
+    _spi.write(0x94);
+    _spi.write(0x80);
+    _spi.write(0x9a);
+    _deselect();  
+
+    _pollbusy(); // Make erase a blocking function
+
+}
+
+
+
+
+
+/*
+ * return the size of the part in bytes
+ */
+
+int AT45::size() { 
+    return _devicesize;
+}
+
+
+
+
+
+/*
+ * return the page size of the part in bytes
+ */
+
+int AT45::pagesize() { 
+    return _pagesize;
+}
+
+
+
+
+
+/*
+ * return the numbers of pages
+ */
+
+int AT45::pages() { 
+    return _pages;
+}
+
+
+  
+
+
+/*
+ * Make sure the Flash isnt already doing something
+ */
+void AT45::_pollbusy() {
+    volatile int busy = 1;  
+    while (busy) {
+        // if bit 7 is set, we can proceed
+        if ( status() & 0x80 ) {
+            busy = 0;}
+    }
+}
+
+
+
+
+
+/*
+ * Make sure the Flash isnt already doing something
+ */
+
+void AT45::pollbusy() {
+    _pollbusy();
+}
+
+
+
+  
+
+/*
+ * This function returns the char
+ */
+
+char AT45::read(int address) {   
+    // return byte from address
+    return (_memread( address ));
+}  
+
+
+
+
+
+/*
+ * This function writes the char to the address supplied
+ * Note : We pass the raw address to the underlying functions
+ */
+
+void AT45::write(int address, char data) {
+
+    _pollbusy();   
+    _flashread(1,address);             // read the Flash page into SRAM buffer
+    _pollbusy();                     // wait for the read to complete
+    _sramwrite(1,address,data);        // Write new data into SRAM
+    _pollbusy();                     // Make sure flash isnt busy
+    _flashwrite(1,address);            // Write back to the page address
+}
+ 
+
+
+
+
+/*
+ * Read from an SRAM buffer
+ * Note : We create buffer and page addresses in _sram and _flash
+ */
+
+int AT45::_sramread(int buffer, int address) {
+
+    int cmd = 0;
+    int baddr = 0;
+  
+    baddr = _getbaddr(address);
+  
+    _select();
+  
+    if(buffer == 1) 
+        {cmd = 0xd4;}
+    else 
+        {cmd = 0xd6;}
+  
+    _spi.write(cmd);
+    _sendaddr (baddr);
+    _spi.write (0x0);   // dont care byte
+    cmd = _spi.write (0x0);  
+  
+    _deselect();            
+ 
+    return (cmd);
+}
+
+
+
+
+
+
+/*
+ * Write to an SRAM buffer
+ * Note : We create buffer and page addresses in _sram and _flash
+ */
+
+void AT45::_sramwrite(int buffer, int address, int data) {
+
+    int cmd = 0;
+    int baddr = 0;
+  
+    baddr = _getbaddr(address);
+  
+    _pollbusy();
+  
+    _select();
+  
+    if (buffer == 1) 
+        {cmd = 0x84;}
+    else 
+        {cmd = 0x87;}
+
+    _spi.write(cmd);
+    _sendaddr (baddr);
+    _spi.write (data);  
+
+    _deselect();            
+}
+
+
+
+
+
+/*
+ * Read from Flash memory into SRAM buffer
+ */
+
+void AT45::_flashread (int buffer, int address) {
+
+    int cmd = 0;
+    int paddr = _getpaddr(address); // calculate page address
+  
+    _pollbusy();  // Check flash is not busy
+    _select();
+      
+    if (buffer == 1)
+        {cmd = 0x53;}
+    else
+        {cmd = 0x55;}
+
+    _spi.write (cmd);  
+    _sendaddr (paddr);
+    _deselect();            
+
+}
+
+
+
+
+
+/*
+ * Write and SRAM buffer back to main memory
+ */
+
+void AT45::_flashwrite (int buffer, int address) {
+
+    int cmd = 0;
+    int paddr = _getpaddr(address);
+ 
+   _pollbusy();  // Check flash is not busy 
+    
+    _select();  
+
+    if (buffer == 1) 
+        {cmd = 0x83;}
+    else 
+        {cmd = 0x86;}
+      
+    _spi.write (cmd);  
+    _sendaddr (paddr);  
+    _deselect();     
+
+    _pollbusy();  // Check flash is not busy 
+  
+}
+
+
+
+
+
+/*
+ * Read directly from main memory
+ */
+
+int AT45::_memread (int address) {
+
+    int data = 0;        
+    int addr;
+
+    addr = _getpaddr(address) | _getbaddr(address);
+
+    _pollbusy();
+
+    _select();
+
+    _spi.write (0xd2);  // Direct read command
+    _sendaddr (addr);
+  
+    // 4 dont care bytes
+    _spi.write (0x00);  
+    _spi.write (0x00);  
+    _spi.write (0x00);  
+    _spi.write (0x00);  
+  
+    // this one clocks the data
+    data = _spi.write (0x00);  
+    _deselect();            
+
+    _pollbusy();
+
+    return data;
+}
+
+
+
+
+
+/*
+ * Sends the three lest significant bytes of the supplied address
+ */
+
+void AT45::_sendaddr (int address) {
+    _spi.write(address >> 16);
+    _spi.write(address >> 8);
+    _spi.write(address);      
+}
+
+
+
+
+
+/*
+ * Return the number of 512 byte blocks in this device
+ */
+
+int AT45::blocks(void) {  
+    return _blocks;
+}
+   
+
+
+
+
+/*
+ * Read the numbered block into the data array supplied
+ */
+
+int AT45::blockread (char* data, int block) {
+
+    // For 256 byte pages, we read two pages
+    if((_pagesize == 256) || (_pagesize == 264)) {
+    
+        int address = block * 512; // This is the start address of the 512 byte block
+            
+        _flashread(1,address); // read the first page of the block into SRAM buffer 1
+        _pollbusy(); // Wait until First page has loaded into buffer 1
+        
+        // I'll do this directly as we are reading back an entire buffer, and this can be done more optimally
+        // than using _sramread
+        _select();
+        _spi.write(0xd4);
+        _sendaddr (0x0);
+        _spi.write (0x0);   // dont care byte
+        
+        for(int i=0;i<256;i++) {
+            data[i] = _spi.write (0x0);  
+        }
+        _deselect();            
+                
+        _flashread(1,address+256); // read the second page of the block into SRAM buffer 2
+        _pollbusy(); // Wait until second page has loaded into buffer 2
+        
+        // Now the second page is loaded, pull this out into the second half of the data buffer
+        // I'll do this directly as we are reading back an entire buffer, and this can be done more optimally
+        // than using _sramread
+        _select();
+        _spi.write(0xd4);
+        _sendaddr (0x0);
+        _spi.write (0x0);   // dont care byte
+        
+        for(int i=0;i<256;i++) {
+            data[256+i] = _spi.write (0x0);  
+        }
+        _deselect();                
+        return (0);
+    }
+    
+    
+    // For 512 byte pages, we read just the single page, transfer it    
+    else if((_pagesize == 512) || (_pagesize == 528)) {
+
+        int address = block * 512; // This is the start address of the 512 byte block
+    
+        _pollbusy(); // Wait until First page has loaded into buffer 1
+        _flashread(1,address); // read the first page of the block into SRAM buffer 1
+        _pollbusy(); // Wait until First page has loaded into buffer 1
+        
+        // Now the page has loaded, simply transfer it from the sram buffer to the data array
+        // I'll do this directly as we are reading back an entire buffer, and this can be done more optimally
+        // than using _sramread
+        _select();
+        _spi.write(0xd4);
+        _sendaddr (0x0);
+        _spi.write (0x0);   // dont care byte
+        
+        for(int i=0;i<512;i++) {
+            data[i] = _spi.write (0x0);  
+        }
+        _deselect();            
+        return (0);
+    }
+
+
+    // For 1024 byte pages, we read just a single page, transfer half of it
+    else if((_pagesize == 1024) || (_pagesize == 1056)) {
+        int address = _getpaddr(block * 512); // This is the start address of the 512 byte block
+
+        _pollbusy(); // Wait until First page has loaded into buffer 1
+    
+        _flashread(1,address); // read the first page of the block into SRAM buffer 1
+
+        _pollbusy(); // Wait until First page has loaded into buffer 1
+        
+        // Now the page has loaded, simply transfer it from the sram buffer to the data array
+        // I'll do this directly as we are reading back an entire buffer, and this can be done more optimally
+        // than using _sramread
+
+        _select();
+        _spi.write(0xd4);
+
+        if (block %2) { // odd numbered block, read from adress 0x200
+            _sendaddr (0x200);
+        }
+        else {// even numbered block, then we are reading from sram buffer 0x0
+            _sendaddr (0x0);
+        }
+
+        
+        _spi.write (0x0);   // dont care byte
+        
+        for(int i=0;i<512;i++) {
+            data[i] = _spi.write (0x0);  
+        }
+        _deselect();            
+        return (0);
+    }
+    
+    else {
+      return (-1); // something isnt configured right
+    }
+}
+
+
+
+
+
+/*
+ * Write the buffer to the numbered block
+ */
+
+int AT45::blockwrite(char* data, int block) {
+
+    // For 256 byte pages, we overwrite two pages
+    if((_pagesize == 256) || (_pagesize == 264)) {
+        
+        // fill the first buffer with the first half of the block
+        // do this directly, for better performance
+        _select();
+        _spi.write(0x84); // writing to buffer #1
+        _sendaddr (0); // we are writing to the entire buffer
+
+        for(int i=0;i<256;i++) {
+            _spi.write (data[i]);  
+        }
+        _deselect();        
+                
+        _flashwrite(1,(block*512));
+
+        // fill the buffer with the second half of the block
+        // do this directly, for better performance
+        _select();
+        _spi.write(0x84); // writing to buffer #1
+        _sendaddr (0); // we are writing to the entire buffer
+
+        for(int i=0;i<256;i++) {
+            _spi.write (data[256+i]);  
+        }
+        _deselect();        
+
+        _flashwrite(1,((block*512)+256));
+    }
+    
+    
+    // For 512 byte pages, we overwrite a single page
+    else if((_pagesize == 512) || (_pagesize == 528)) {
+    
+        // fill the first buffer with the block data
+        // do this directly, for better performance
+        _select();
+        _spi.write(0x84); // writing to buffer #1
+        _sendaddr (0); // we are writing to the entire buffer
+
+        for(int i=0;i<512;i++) {
+            _spi.write (data[i]);  
+        }
+        _deselect();        
+        
+        _pollbusy(); // make sure the Flahs isnt busy
+                
+        // issue command to write buffer 1 to the appropraite flash page
+        _select();  
+        _spi.write (0x83);  
+        _sendaddr (_getpaddr(block * 512));  
+        _deselect();     
+        _pollbusy(); // make sure the Flahs isnt busy           
+    }
+
+
+    // For 1024 byte pages, we do a read modify write
+    // must make sure we overwrite the right half of the page!
+    else if((_pagesize == 1024) || (_pagesize == 1056)) {
+
+        _pollbusy(); // make sure the flash isnt busy
+
+        int address = _getpaddr(block*512);
+
+        // Read the page into sram
+        _flashread(1,address);  
+        
+        // wait for this operation to complete
+        _pollbusy();
+        
+        // Overwrite the appropriate half
+        // do this directly, for better performance
+        _select();
+        _spi.write(0x84); // writing to buffer #1
+
+        if(block%2) {  // this is an odd block number, overwrite second half of buffer
+            _sendaddr (0x200); // we are writing to the entire buffer
+        }
+        else {  // this is an even block, overwrite the first half
+            _sendaddr (0x0); // we are writing to the entire buffer
+        }
+
+        for(int i=0;i<512;i++) {
+            _spi.write (data[i]);  
+        }
+        _deselect();        
+        
+        // Write the page back
+        _pollbusy();
+        _flashwrite(1,address); 
+        
+    }
+
+
+    // Something has gone wrong
+    else {
+      return (-1);
+    }
+
+    return (0);
+}
+
+
+/*
+ * Return the number of 512 byte blocks in this device
+ */
+void blockerase (int block) {}
+
+
+
+/*
+ * returns the number of buffer to use
+ * If page is already open, use it
+ * If one of the buffers is unused, use it
+ * else evict the least recently used.
+
+ */
+int _allocatebuffer (int address) {
+
+  int buf = 0;
+  // is page already open in buffer 1?
+  // is page already open in buffer 2
+  // is buffer 1 unusued?
+  // is buffer 2 unused
+  // evict LRU
+  
+  return (buf); 
+  
+}
+
+
+
+/*
+ * write the buffer back to flash
+ * set it as LRU
+ * make _bufferNaddress = -1
+ */
+void _flushbuffer (int buffer) {
+
+  // is page already open in buffer 1?
+  // is page already open in buffer 2
+  // is buffer 1 unusued?
+  // is buffer 2 unused
+  // evict LRU
+  
+}
+
+
+
+
+
+   
+    
\ No newline at end of file