File content as of revision 1:bb2b1e4bfb6e:

/* Cypress FM25W256 F-RAM component library
 *
 * Copyright (c) 2016 ARM Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *  *
 *  @author  Toyomasa Watarai
 *  @version 1.0
 *  @date    5-March-2016
 *
 *  http://www.cypress.com/products/nonvolatile-ram
 *  http://www.cypress.com/documentation/datasheets/fm25w256-256-kbit-32-k-8-serial-spi-f-ram?source=search&keywords=FM25W256&cat=technical_documents
 *
 */
 
#include "mbed.h"

#ifndef __FM25W256_HEAD__
#define __FM25W256_HEAD__

#define CMD_WREN   0x06
#define CMD_WRDI   0x04
#define CMD_RDSR   0x05
#define CMD_WRSR   0x01
#define CMD_READ   0x03
#define CMD_WRITE  0x02

#define FM25W256_CLK (20000000) // SPI clock 20MHz

/** An interface for the Cypress 32k byte FM25W256 F-RAM over SPI

@code
#include "mbed.h"
#include "FM25W256.h"

Serial pc(USBTX, USBRX);
FM25W256 f_ram(dp2, dp1, dp6, dp18);

int main()
{
    uint8_t buf[16];
    // Fill buffer
    for(int i=0; i<16; i++) {
        buf[i] = i;
    }
    // Write data to F-RAM
    f_ram.write(0, buf, 16);

    // Read data from F-RAM
    uint16_t adrs = 0;
    for(int i=0; i<16; i++) {
        pc.printf("0x%04X : ", i * 16);
        for(int j=0; j<16; j++) {
            pc.printf("%02X ", f_ram.read(adrs++));
        }
        pc.printf("\n");
    }
    
    while(1) {
    }
}
*/
class FM25W256 {
public:

    enum E_WP {
        BANK_NONE = 0,
        BANK_UPPER_QUARTER = 1,
        BANK_UPPER_HALF = 2,
        BANK_ALL = 3
    };
    
/** Create an interface
*
* @param mosi  SPI master-out-slave-in
* @param miso  SPI master-in-slave-out
* @param clk   SPI clock
* @param cs    chip select pin - any free Digital pin will do
*/
    FM25W256(PinName mosi, PinName miso, PinName clk, PinName cs);

/** Create an interface
*
* @param &spi  SPI instance
* @param cs    chip select pin - any free Digital pin will do
*/
    FM25W256(SPI &spi, PinName cs);
    
/** write a byte to F-RAM
* @param address    The address F-RAM to write to
* @param data       The byte to write there
*/
    void write(uint16_t address, uint8_t data);

/** write multiple bytes to F-RAM from a buffer
* @param address    The F-RAM address write to
* @param data       The buffer to write from
* @param size       The number of bytes to write
*/
    void write(uint16_t address, uint8_t *data, uint16_t size);

/** read a byte from F-RAM
* @param address    The address to read from
* @return the character at that address
*/
    uint8_t read(uint16_t address);

/** read multiple bytes from F-RAM into a buffer
* @param address    The F-RAM address to read from
* @param data       The buffer to read into (must be big enough!)
* @param size       The number of bytes to read
*/
    void read(uint16_t address, uint8_t *data, uint16_t size);

/** write a byte to the status register
* @param data  The byte to write the register
*/
    void wirte_status(uint8_t data);

/** read a byte from the status register
* @return the character at the register
*/
    uint8_t read_status();

/** Set write protect mode
* @param bp   E_WP enum value
*/
    void set_write_protect(E_WP bp);

/** Set write protect to non-protect mode
*/
    void clear_write_protect();

protected:
    SPI _spi;
    DigitalOut _cs;
};

#endif