Revision 0:0411eff88bac, committed 2018-07-23

Comitter:

JackB

Date:

Mon Jul 23 12:23:33 2018 +0000

Commit message:

FRAM

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FRAMSPI.cpp	Mon Jul 23 12:23:33 2018 +0000
@@ -0,0 +1,81 @@
+/* FRAMSPI - Ramtron FRAM FM24VXX series driver
+* Copyright (c) 2012 Oleg Evsegneev
+* Released under the MIT License: http://mbed.org/license/mit
+*
+* Datasheet http://www.ramtron.com/files/datasheets/FM25V02_ds.pdf
+*/
+ 
+#include "mbed.h"
+#include "FRAMSPI.h"
+ 
+FRAMSPI::FRAMSPI(SPI& spi, PinName ncs) : _spi(spi), _ncs(ncs) {
+    deselect();
+}
+ 
+void FRAMSPI::select() {
+    _ncs = 0;
+}
+ 
+void FRAMSPI::deselect() {
+    _ncs = 1;
+}
+ 
+void FRAMSPI::readID( char *buff ) {
+    select();
+    _spi.write(READ_SN);
+    for( int i=0; i<8; i++ )
+        buff[i] = (char) _spi.write(0);
+    deselect();
+}
+ 
+void FRAMSPI::readSN( char *buff ) {
+    select();
+    _spi.write(READ_SN);
+    for( int i=0; i<2; i++ )
+        buff[i] = (char) _spi.write(0);
+    deselect();
+}
+ 
+void FRAMSPI::prepareCommand(char cmd, int addr) {
+    if( cmd == WRITE ){
+        select();
+        _spi.write(WRITE_ENABLED);
+        deselect();
+    }
+    select();
+    _spi.write(cmd);
+    _spi.write(addr >> 8);
+    _spi.write(addr & 0xFF);
+}
+ 
+// write
+void FRAMSPI::write(int addr, char byte) {
+    prepareCommand(WRITE, addr);
+    _spi.write(byte);
+    deselect();
+}
+ 
+void FRAMSPI::write(int addr, char *buff, int cnt) {
+    prepareCommand(WRITE, addr);
+    for (int i = 0; i < cnt; i++) {
+        _spi.write(buff[i]);
+    }
+    deselect();
+}
+ 
+// read
+char FRAMSPI::read(int addr) {
+    char res;
+    prepareCommand(READ, addr);
+    res = _spi.write(0);
+    deselect();
+    return res;
+}
+ 
+void FRAMSPI::read(int addr, char * buff, int cnt) {
+    prepareCommand(READ, addr);
+    for (int i = 0; i < cnt; i++) {
+        buff[i] = _spi.write(0);
+    }
+    deselect();
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FRAMSPI.h	Mon Jul 23 12:23:33 2018 +0000
@@ -0,0 +1,107 @@
+/* FRAM_SPI - Ramtron FRAM FM24VXX series driver
+* Copyright (c) 2012 Oleg Evsegneev
+* Released under the MIT License: http://mbed.org/license/mit
+*
+* Datasheet http://www.ramtron.com/files/datasheets/FM25V02_ds.pdf
+*/
+ 
+#ifndef  FRAMSPI_
+#define  FRAMSPI_
+ 
+#include "mbed.h"
+ 
+// commands
+#define READ            0x03
+#define WRITE           0x02
+#define READ_STATUS     0x05 // RDSR
+#define WRITE_ENABLED   0x06 // WREN
+#define WRITE_STATUS    0x01 // WRSR
+#define READ_ID         0x9F // RDID
+#define READ_SN         0xC3 // RSN
+ 
+/** An interface for the Ramtron FM25VXX FRAM over SPI
+*
+* 
+*
+* @code
+* #include "mbed.h"
+* #include "FRAMSPI.h"
+* 
+* SPI spi(p5,p6,p7);
+* FRAMSPI fram(spi,p8);
+* Serial pc(USBTX, USBRX);
+* 
+* int main() {
+*     char wdata[] = "Hello world!";
+*     char rdata[14];
+* 
+*     fram.write(0, wdata, 13); // 12 symbols + zero terminator
+*     fram.read(0, rdata, 13);
+* 
+*     pc.printf("data: %s", rdata);
+* }
+* @endcode
+* connections:
+* chip pin 1 to any GPIO. Chip select (!S)
+* chip pin 2 SO to MISO. Write (!W)
+* chip pin 3 to Vout or N/C
+* chip pin 4 to Gnd
+* chip pin 5 SI to MOSI
+* chip pin 6 SCK to sck 
+* chip pin 7 to Vout. !Hold
+* chip pin 8 to Vout
+*/
+ 
+class FRAMSPI {
+ 
+public:
+    /** Create an interface
+    *
+    * @param spi    An SPI object
+    * @param ncs    Chip select pin
+    */
+    FRAMSPI(SPI& spi, PinName ncs);
+ 
+    /** read chip 8 byte device ID
+    */
+    void readID(char *buff);
+ 
+    /** read chip 2 byte serial number
+    */
+    void readSN(char *buff);
+ 
+    /** read a byte from FRAM
+    * @param addr    The address to read from
+    * @return the byte at that address
+    */
+    char read(int addr);
+ 
+    /** read multiple bytes from FRAM into a buffer
+    * @param addr    The FRAM address to read from
+    * @param buff     The buffer to read into (must be big enough!)
+    * @param cnt      The number of bytes to read
+    */
+    void read(int addr, char *buff, int cnt);
+ 
+    /** write a byte to FRAM
+    * @param addr    The address SFRAM to write to
+    * @param data       The byte to write there
+    */
+    void write(int addr, char data);
+ 
+    /** write multiple bytes to FRAM from a buffer
+    * @param addr    The FRAM address write to
+    * @param buff     The buffer to write from
+    * @param cnt      The number of bytes to write
+    */
+    void write(int addr, char *buff, int cnt);
+ 
+private:
+    SPI& _spi;
+    DigitalOut _ncs;
+    void prepareCommand(char cmd, int addr);
+    void select();
+    void deselect();
+};
+ 
+#endif