Diff: main.cpp

Revision:

0:4d4598bd9119

Child:

1:3a2094fa7c4c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Nov 09 01:57:47 2012 +0000
@@ -0,0 +1,126 @@
+/*
+ * SPI RAM NP8P128A13TSM60E (Micron)
+ *   128Mbit
+ */
+#include "mbed.h"
+
+#define CMD_WREN    0x06    // Write enable
+#define CMD_WRDI    0x04    // Write disable
+#define CMD_RDID    0x9f    // Read identification 
+#define CMD_RDSR    0x05    // Read status register
+#define CMD_WRSR    0x01    // Write status registe
+#define CMD_READ    0x03    // Read data bytes
+#define CMD_FREAD   0x0b    // Read data bytes at higher speed
+#define CMD_PP      0x02    // Page program (legacy program)
+#define CMD_PP_BA   0x22    // Page program (bit-alterable write)
+#define CMD_PP_1S   0xd1    // Page program (On all 1s)
+#define CMD_SE      0xd8    // Sector erase
+
+DigitalOut myled(LED1);
+Serial pc(USBTX, USBRX);
+
+SPI spi(p11, p12, p13); // mosi, miso, sclk
+DigitalOut cs(p14), hold(p15), reset(p16);
+
+int ram_status () {
+    int r;
+
+    cs = 0;
+    spi.write(CMD_RDSR);
+    r = spi.write(0);
+    cs = 1;
+    return r;
+}
+
+int ram_write (int addr, char *buf, int len) {
+    int i;
+
+    while (ram_status() & 1) {
+        // write in progress
+        wait_us(10);
+    }
+
+    cs = 0;
+    spi.write(CMD_WREN);
+    cs = 1;
+    wait_us(10);
+
+    cs = 0;
+    spi.write(CMD_PP_BA);
+    spi.write((addr >> 16) & 0xff);
+    spi.write((addr >> 8) & 0xff);
+    spi.write(addr & 0xff);
+
+    len = len - (addr & 0x1f);
+    for (i = 0; i < len; i ++) {
+        spi.write(buf[i]);
+    }
+    cs = 1;
+    return i;
+}
+
+int ram_read (int addr, char *buf, int len) {
+    int i;
+
+    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;
+}
+
+int main() {
+    int i;
+    char buf[64];
+
+    cs = 1;
+    hold = 1;
+    reset = 0;
+    pc.baud(115200);
+    wait_ms(10);
+    reset = 1;
+    wait_ms(500);
+    
+    cs = 0;
+    spi.write(CMD_RDID);
+    printf("RAM Manufacturer ID : %02x\r\n", spi.write(0));
+    i = (spi.write(0) << 8) | spi.write(0);
+    printf("RAM Device ID : %04x\r\n", i);
+    cs = 1;
+    wait_ms(10);
+
+    printf("Status Register : %02x\r\n", ram_status());
+
+    printf("RAM write\r\n");
+    strcpy(buf, "Hello!");
+    ram_write(0, buf, 6);
+
+    for (i = 0; i < 64; i ++) {
+        buf[i] = i;
+    }
+    ram_write(6, buf, 64);
+
+    wait_ms(500);
+    memset(buf, 0, 64);
+
+    printf("RAM read\r\n");
+    ram_read(0, buf, 64);
+    for (i = 0; i < 64; i ++) {
+        printf(" %02x", buf[i]);
+        if ((i & 0x0f) == 0x0f)
+            printf("\r\n");
+    }
+
+    while(1) {
+        myled = 1;
+        wait(0.2);
+        myled = 0;
+        wait(0.2);
+    }
+}