Diff: main.cpp

Revision:

0:e37acb3371f0

Child:

1:d840fdc82450

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Feb 18 18:42:21 2015 +0000
@@ -0,0 +1,195 @@
+/*
+ * Everspin Technologies - The MRAM Company
+ *  MR10Q010-EVAL SHIELD
+ *  MR10Q010CSCR - 1Mb MRAM (128Kx8), 40MHz SPI
+ */
+
+
+#include "mbed.h"
+
+#define SERIAL_BAUD 115200
+#define SPI_FREQ 40000000
+
+//SPI Mode Commands for MR10Q010
+#define CMD_RDSR 0x05
+#define CMD_WREN 0x06
+#define CMD_WRDI 0x04
+#define CMD_WRSR 0x01
+#define CMD_READ 0x03
+#define CMD_FREAD 0x0B
+#define CMD_WRITE 0x02
+#define CMD_SLEEP 0xB9
+#define CMD_WAKE 0xAB
+#define CMD_TDET 0x17
+#define CMD_RDID 0x48
+
+//pin setup for interfacing with the device
+SPI MR10Q010(D11, D12, D13); // mosi, miso, sclk
+DigitalOut SS(D10);
+DigitalOut WP(D9);
+DigitalOut HOLD(D8);
+
+//create a serial object for output to the terminal
+Serial pc(SERIAL_TX, SERIAL_RX);
+
+char wrbuf[256] = {0};
+char rdbuf[256] = {0};
+
+//MR10Q010 read wrapper function
+int mram_read (int addr, char *buf, int len)
+{
+    int i;
+
+    SS=0;
+    MR10Q010.write(CMD_READ);
+    MR10Q010.write((addr >> 16) & 0xff);
+    MR10Q010.write((addr >> 8) & 0xff);
+    MR10Q010.write(addr & 0xff);
+
+    for (i = 0; i < len; i ++) {
+        rdbuf[i] = MR10Q010.write(0);
+    }
+
+    SS=1;
+    return 1;
+
+}
+
+//MR10Q010 write wrapper function
+int mram_write (int addr, char *buf, int len)
+{
+    int i;
+
+    SS=0;
+    MR10Q010.write(CMD_WRITE);
+    MR10Q010.write((addr >> 16) & 0xff);
+    MR10Q010.write((addr >> 8) & 0xff);
+    MR10Q010.write(addr & 0xff);
+
+    for (i = 0; i < len; i ++) {
+        MR10Q010.write(wrbuf[i]);
+    }
+
+    SS=1;
+    return 1;
+}
+
+//Enable writes
+int mram_wren (void)
+{
+
+    WP=1;
+
+    SS=0;
+    MR10Q010.write(CMD_WREN);
+    SS=1;
+
+    return 1;
+}
+
+//Disable writes
+int mram_wrdi (void)
+{
+
+    SS=0;
+    MR10Q010.write(CMD_WRDI);
+    SS=1;
+
+    WP=0;
+    return 1;
+}
+
+
+
+//main function showing basic mram function usage with a nvm performance test
+int main()
+{
+    int i,j;
+    int run_cnt = 0;
+    Timer t;
+
+    HOLD=1;   //make sure HOLD is released
+
+    MR10Q010.frequency(SPI_FREQ); //setup SPI frequency
+    pc.baud(SERIAL_BAUD);  //setup UART baud
+    memset(rdbuf,0,256);  //init read buffer
+
+    pc.printf("\r\n\r\n");
+    pc.printf("================================================\r\n");
+    pc.printf("||           Everspin Technologies            ||\r\n");
+    pc.printf("||              The MRAM Company              ||\r\n");
+    pc.printf("================================================\r\n");
+    pc.printf("||           MR10Q010 mbed Example            ||\r\n");
+    pc.printf("||            1Mb MRAM, 40MHz SPI             ||\r\n");
+    pc.printf("================================================\r\n");
+
+    //check the last word of the mem to see if this demo has ever been run on the mram...  initialize if not.
+    mram_read(0x1FFFF, rdbuf, 1);
+    if(rdbuf[0] != 0xAA) {
+        mram_wren();  //Enable writes to MRAM
+        pc.printf("First time running...  init MRAM!\r\n");
+        memset(wrbuf,0,256);
+        mram_write(0, wrbuf, 256);
+        wrbuf[0] = 0xAA;
+        mram_write(0x1FFFF, wrbuf, 1);
+        mram_wrdi();
+    }
+
+    while(1) {
+        
+        mram_read(0, rdbuf, 256);
+        run_cnt = rdbuf[0] + 1;
+
+        pc.printf("MRAM Read: Show Test Count\r\n");
+    
+        for (i = 0; i < 256; i ++) {
+            pc.printf(" %02x", rdbuf[i]);
+            if ((i & 0x0f) == 0x0f)
+                pc.printf("\r\n");
+        }
+    
+        pc.printf("\r\nWrite/Read time for 1048576 bits @ 40MHz:\r\n\r\n");
+        mram_wren();
+        pc.printf("MRAM writing\r\n");
+        t.reset();
+        t.start();
+        for (i = 0; i < 0x20000; i += 256) {
+            for(j = 0; j < 256; j++) {
+                wrbuf[j] = run_cnt & 0xff;
+            }
+            mram_write(i, wrbuf, 256);
+            if ((i & 0x0fff) == 0) pc.printf(".");
+        }
+        t.stop();
+        pc.printf("\r\nTime: %f s   Rate: %f KBytes/sec\r\n\r\n", t.read(), (float)0x20000 / 1024 / t.read());
+        mram_wrdi();
+    
+        printf("MRAM reading (and error checking)\r\n");
+        t.reset();
+        t.start();
+        for (i = 0; i < 0x20000; i += 256) {
+            mram_read(i, rdbuf, 256);
+            for(j = 0; j < 256; j++) {
+                if (rdbuf[j] != (run_cnt & 0xff)) {
+                    pc.printf("Error %d\r\n", i+j);
+                    break;
+                }
+            }
+            if ((i & 0x0fff) == 0) pc.printf(".");
+        }
+        t.stop();
+        pc.printf("\r\nTime: %f s   Rate: %f KBytes/sec\r\n\r\n", t.read(), 0x20000 / 1024 / t.read());
+    
+        mram_wren();
+        wrbuf[0] = 0xAA;  //rewrite init word
+        mram_write(0x1FFFF, wrbuf, 1);
+        memset(rdbuf, 0, 256);
+        mram_wrdi();
+        
+        pc.printf("Press any key to run again...\r\n\r\n\r\n");
+        
+        while(!pc.getc());
+
+    }
+
+}