FM25W256.h

00001 /* Cypress FM25W256 F-RAM component library
00002  *
00003  * Copyright (c) 2016 ARM Limited
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  *  *
00017  *  @author  Toyomasa Watarai
00018  *  @version 1.0
00019  *  @date    5-March-2016
00020  *
00021  *  http://www.cypress.com/products/nonvolatile-ram
00022  *  http://www.cypress.com/documentation/datasheets/fm25w256-256-kbit-32-k-8-serial-spi-f-ram?source=search&keywords=FM25W256&cat=technical_documents
00023  *
00024  */
00025  
00026 #include "mbed.h"
00027 
00028 #ifndef __FM25W256_HEAD__
00029 #define __FM25W256_HEAD__
00030 
00031 #define CMD_WREN   0x06
00032 #define CMD_WRDI   0x04
00033 #define CMD_RDSR   0x05
00034 #define CMD_WRSR   0x01
00035 #define CMD_READ   0x03
00036 #define CMD_WRITE  0x02
00037 
00038 #define FM25W256_CLK (20000000) // SPI clock 20MHz
00039 
00040 /** An interface for the Cypress 32k byte FM25W256 F-RAM over SPI
00041  * 
00042  * @code
00043  * #include "mbed.h"
00044  * #include "FM25W256.h"
00045  * 
00046  * Serial pc(USBTX, USBRX);
00047  * FM25W256 f_ram(dp2, dp1, dp6, dp18);
00048  * 
00049  * int main()
00050  * {
00051  *     uint8_t buf[16];
00052  *     // Fill buffer
00053  *     for(int i=0; i<16; i++) {
00054  *         buf[i] = i;
00055  *     }
00056  *     // Write data to F-RAM
00057  *     f_ram.write(0, buf, 16);
00058  * 
00059  *     // Read data from F-RAM
00060  *     uint16_t adrs = 0;
00061  *     for(int i=0; i<16; i++) {
00062  *         pc.printf("0x%04X : ", i * 16);
00063  *         for(int j=0; j<16; j++) {
00064  *             pc.printf("%02X ", f_ram.read(adrs++));
00065  *         }
00066  *         pc.printf("\n");
00067  *     }
00068  *     
00069  *     while(1) {
00070  *     }
00071  * }
00072  * @endcode
00073  */
00074 class FM25W256 {
00075 public:
00076 
00077     enum E_WP {
00078         BANK_NONE = 0,
00079         BANK_UPPER_QUARTER = 1,
00080         BANK_UPPER_HALF = 2,
00081         BANK_ALL = 3
00082     };
00083     
00084 /** Create an interface
00085  *
00086  * @param mosi  SPI master-out-slave-in
00087  * @param miso  SPI master-in-slave-out
00088  * @param clk   SPI clock
00089  * @param cs    chip select pin - any free Digital pin will do
00090  */
00091     FM25W256(PinName mosi, PinName miso, PinName clk, PinName cs);
00092 
00093 /** Create an interface
00094  *
00095  * @param &spi  SPI instance
00096  * @param cs    chip select pin - any free Digital pin will do
00097  */
00098     FM25W256(SPI &spi, PinName cs);
00099     
00100 /** write a byte to F-RAM
00101  * @param address    The address F-RAM to write to
00102  * @param data       The byte to write there
00103  */
00104     void write(uint16_t address, uint8_t data);
00105 
00106 /** write multiple bytes to F-RAM from a buffer
00107  * @param address    The F-RAM address write to
00108  * @param data       The buffer to write from
00109  * @param size       The number of bytes to write
00110  */
00111     void write(uint16_t address, uint8_t *data, uint16_t size);
00112 
00113 /** read a byte from F-RAM
00114  * @param address    The address to read from
00115  * @return the character at that address
00116  */
00117     uint8_t read(uint16_t address);
00118 
00119 /** read multiple bytes from F-RAM into a buffer
00120  * @param address    The F-RAM address to read from
00121  * @param data       The buffer to read into (must be big enough!)
00122  * @param size       The number of bytes to read
00123  */
00124     void read(uint16_t address, uint8_t *data, uint16_t size);
00125 
00126 /** write a byte to the status register
00127  * @param data  The byte to write the register
00128  */
00129     void wirte_status(uint8_t data);
00130 
00131 /** read a byte from the status register
00132  * @return the character at the register
00133  */
00134     uint8_t read_status();
00135 
00136 /** Set write protect mode
00137  * @param bp   E_WP enum value
00138  */
00139     void set_write_protect(E_WP bp);
00140 
00141 /** Set write protect to non-protect mode
00142  */
00143     void clear_write_protect();
00144 
00145 protected:
00146     SPI _spi;
00147     DigitalOut _cs;
00148 };
00149 
00150 #endif