Diff: 24LC64_eeprom.cpp

Revision:

0:435bf84ce48a

Child:

1:0fabe6fdb55b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/24LC64_eeprom.cpp	Thu Mar 01 11:29:28 2018 +0000
@@ -0,0 +1,109 @@
+#include "mbed.h"
+//#include "rtos.h"
+#include "BufferedSerial.h"
+extern  BufferedSerial pc;
+extern  I2C i2c;
+    //  Code for 24LC64 eeprom
+    //  Code based on earlier work using memory FM24W256, also at i2c address 0xa0;
+ 
+const int addr_rd = 0xa1;  //  set bit 0 for read, clear bit 0 for write
+const int addr_wr = 0xa0;  //  set bit 0 for read, clear bit 0 for write
+const int ACK     = 1;
+
+bool    ack_poll    ()  {   //  wait short while for any previous memory operation to complete
+    const int poll_tries    = 40;
+    int poll_count = 0;
+    bool    i2cfree = false;
+    while   (poll_count++ < poll_tries && !i2cfree)  {
+        i2c.start   ();
+        if  (i2c.write(addr_wr) == ACK)
+            i2cfree = true;
+        else
+//            Thread::wait(1);   //   1ms
+            wait   (1);
+    }
+//    pc.printf   ("ack_poll, count = %d, i2cfree = %s\r\n", poll_count, i2cfree ? "true" : "false");
+    return  i2cfree;
+}
+
+bool    set_24LC64_internal_address (int    start_addr)   {
+    if  (!ack_poll())
+    {
+        pc.printf   ("Err in set_24LC64_internal_address, no ACK writing device address byte\r\n");
+        i2c.stop();
+        return  false;
+    }
+    int err = 0;
+    if  (i2c.write(start_addr >> 8)   != ACK) err++;
+    if  (i2c.write(start_addr & 0xff) != ACK) err++;
+    if  (err)   {
+        pc.printf   ("In set_24LC64_internal_address, Believe Device present, failed in writing 2 mem addr bytes %d\r\n", err);
+        i2c.stop();
+        return  false;
+    }
+    return  true;
+}
+
+bool    wr_24LC64  (int start_addr, char * source, int length)   {
+    int err = 0;
+    if(length < 1 || length > 32)   {
+        pc.printf   ("Length out of range %d in wr_24LC64\r\n", length);
+        return  false;
+    }
+    if  (!set_24LC64_internal_address   (start_addr))   {
+        pc.printf   ("In wr_24LC64, Believe Device present, failed in writing 2 mem addr bytes %d\r\n", err);
+        return  false;
+    }
+    while(length--)
+        err += ACK - i2c.write(*source++);
+    i2c.stop();
+    if  (err)   {
+        pc.printf   ("in wr_24LC64, device thought good, mem addr write worked, failed writing string\r\n");
+        return  false;
+    }
+    pc.printf   ("In wr_24LC64 No Errors Found!\r\n");
+    return  true;
+}
+
+bool rd_24LC64  (int start_addr, char * dest, int length)   {
+    int acknak = ACK;
+    if(length < 1)
+        return false;
+    if  (!set_24LC64_internal_address   (start_addr))   {
+        pc.printf   ("In rd_24LC64, failed to set_ramaddr\r\n");
+        return  false;
+    }
+    i2c.start();
+    if  (i2c.write(addr_rd) != ACK) {
+        pc.printf   ("Errors in rd_24LC64 sending addr_rd\r\n");
+        return  false;
+    }
+    while(length--) {
+        if(length == 0)
+            acknak = 0;
+        *dest++ = i2c.read(acknak);
+    }
+    i2c.stop();
+    return  true;
+}
+
+int check_24LC64   ()  {     //  Call from near top of main() to init i2c bus
+    i2c.frequency(400000);      //  Speed 400000 max.
+    int last_found = 0, q;      //  Note address bits 3-1 to match addr pins on device
+    for (int i = 0; i < 255; i += 2)    {   //  Search for devices at all possible i2c addresses
+        i2c.start();
+        q = i2c.write(i);   //  may return error code 2 when no start issued
+        switch  (q) {
+            case    ACK:
+                pc.printf   ("I2C device found at 0x%x\r\n", i);
+                last_found = i;
+            case    2:      //  Device not seen at this address
+            break;
+            default:
+                pc.printf   ("Unknown error %d in check_24LC64\r\n", q);
+            break;
+        }
+    }
+    i2c.stop();
+    return  last_found;
+}