FM25W256.cpp

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 #include "FM25W256.h"
00028 
00029 FM25W256::FM25W256(PinName mosi, PinName miso, PinName clk, PinName cs)
00030     : _spi(mosi, miso, clk), _cs(cs)
00031 {
00032     _spi.format(8, 0);
00033     _spi.frequency(FM25W256_CLK);
00034     _cs = 1;
00035     wait_ms(1); // tPU = 1ms (min.)
00036 }
00037 
00038 FM25W256::FM25W256(SPI &spi, PinName cs)
00039     : _spi(spi), _cs(cs) 
00040 {
00041     _spi.format(8, 0);
00042     _spi.frequency(FM25W256_CLK);
00043     _cs = 1;
00044     wait_ms(1); // tPU = 1ms (min.)
00045 }
00046 
00047 void FM25W256::write(uint16_t address, uint8_t data)
00048 {
00049     _cs = 0;
00050     _spi.write(CMD_WREN);
00051     _cs = 1;
00052 
00053     _cs = 0;
00054     _spi.write(CMD_WRITE);
00055     _spi.write(address >> 8);
00056     _spi.write(address & 0xFF);
00057     _spi.write(data);
00058     _cs = 1;
00059 }
00060 
00061 void FM25W256::write(uint16_t address, uint8_t *data, uint16_t size)
00062 {
00063     _cs = 0;
00064     _spi.write(CMD_WREN);
00065     _cs = 1;
00066 
00067     _cs = 0;
00068     _spi.write(CMD_WRITE);
00069     _spi.write(address >> 8);
00070     _spi.write(address & 0xFF);
00071     while(size--) {
00072         _spi.write(*data++);
00073     }
00074     _cs = 1;
00075 }
00076 
00077 uint8_t FM25W256::read(uint16_t address)
00078 {
00079     uint8_t data;
00080 
00081     _cs = 0;
00082     _spi.write(CMD_READ);
00083     _spi.write(address >> 8);
00084     _spi.write(address & 0xFF);
00085     data = _spi.write(0);
00086     _cs = 1;
00087 
00088     return data;
00089 }
00090 
00091 void FM25W256::read(uint16_t address, uint8_t *buf, uint16_t size)
00092 {
00093     _cs = 0;
00094     _spi.write(CMD_READ);
00095     _spi.write(address >> 8);
00096     _spi.write(address & 0xFF);
00097     while (size--) {
00098         *buf++ = _spi.write(0);
00099     }
00100     _cs = 1;
00101 }
00102 
00103 void FM25W256::wirte_status(uint8_t data)
00104 {
00105     _cs = 0;
00106     _spi.write(CMD_WREN);
00107     _cs = 1;
00108 
00109     _cs = 0;
00110     _spi.write(CMD_WRSR);
00111     _spi.write(data);
00112     _cs = 1;
00113 }
00114 
00115 uint8_t FM25W256::read_status()
00116 {
00117     uint8_t data;
00118     _cs = 0;
00119     _spi.write(CMD_RDSR);
00120     data = _spi.write(0);
00121     _cs = 1;
00122     
00123     return data;
00124 }
00125 
00126 void FM25W256::set_write_protect(E_WP bp)
00127 {
00128     // Set WPEN, BP0 and BP1
00129     wirte_status((1 << 7) | (bp << 2));
00130 }
00131 
00132 void FM25W256::clear_write_protect()
00133 {
00134     wirte_status(0);
00135 }
00136