Create SPIFlash.cpp

SPIFlash.cpp

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+/*
+ * Copyright (c) 2013 by Felix Rusu <felix@lowpowerlab.com>
+ * SPI Flash memory library for arduino/moteino.
+ * This works with 256byte/page SPI flash memory
+ * For instance a 4MBit (512Kbyte) flash chip will have 2048 pages: 256*2048 = 524288 bytes (512Kbytes)
+ * Minimal modifications should allow chips that have different page size but modifications
+ * DEPENDS ON: Arduino SPI library
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either the GNU General Public License version 2
+ * or the GNU Lesser General Public License version 2.1, both as
+ * published by the Free Software Foundation.
+ */
+
+#include <SPIFlash.h>
+
+/// Constructor. JedecID is optional but recommended, since this will ensure that the device is present and has a valid response
+/// get this from the datasheet of your flash chip
+/// Example for Atmel-Adesto 4Mbit AT25DF041A: 0x1F44 (page 27: http://www.adestotech.com/sites/default/files/datasheets/doc3668.pdf)
+/// Example for Winbond 4Mbit W25X40CL: 0x9F30 (page 14: http://www.winbond.com/NR/rdonlyres/6E25084C-0BFE-4B25-903D-AE10221A0929/0/W25X40CL.pdf)
+SPIFlash::SPIFlash(uint8_t slaveSelectPin, uint16_t jedecID) {
+  _slaveSelectPin = slaveSelectPin;
+  _jedecID = jedecID;
+}
+
+/// Select the flash chip
+void SPIFlash::select() {
+  noInterrupts();
+  digitalWrite(_slaveSelectPin, LOW);
+}
+
+/// UNselect the flash chip
+void SPIFlash::unselect() {
+  digitalWrite(_slaveSelectPin, HIGH);
+  interrupts();
+}
+
+/// setup SPI, read device ID etc...
+boolean SPIFlash::initialize()
+{
+  pinMode(_slaveSelectPin, OUTPUT);
+  unselect();
+  SPI.setDataMode(SPI_MODE0);
+  SPI.setBitOrder(MSBFIRST);
+  SPI.setClockDivider(SPI_CLOCK_DIV2); //max speed, except on Due which can run at system clock speed
+  SPI.begin();
+
+  if (_jedecID == 0 || readDeviceId() == _jedecID) {
+    command(SPIFLASH_STATUSWRITE, true); // Write Status Register
+    SPI.transfer(0);                     // Global Unprotect
+    unselect();
+    return true;
+  }
+  return false;
+}
+
+/// Get the manufacturer and device ID bytes (as a short word)
+word SPIFlash::readDeviceId()
+{
+  command(SPIFLASH_IDREAD); // Read JEDEC ID
+  word jedecid = SPI.transfer(0) << 8;
+  jedecid |= SPI.transfer(0);
+  unselect();
+  return jedecid;
+}
+
+/// read 1 byte from flash memory
+byte SPIFlash::readByte(long addr) {
+  command(SPIFLASH_ARRAYREADLOWFREQ);
+  SPI.transfer(addr >> 16);
+  SPI.transfer(addr >> 8);
+  SPI.transfer(addr);
+  byte result = SPI.transfer(0);
+  unselect();
+  return result;
+}
+
+/// read unlimited # of bytes
+void SPIFlash::readBytes(long addr, void* buf, word len) {
+  command(SPIFLASH_ARRAYREAD);
+  SPI.transfer(addr >> 16);
+  SPI.transfer(addr >> 8);
+  SPI.transfer(addr);
+  SPI.transfer(0); //"dont care"
+  for (word i = 0; i < len; ++i)
+    ((byte*) buf)[i] = SPI.transfer(0);
+  unselect();
+}
+
+/// Send a command to the flash chip, pass TRUE for isWrite when its a write command
+void SPIFlash::command(byte cmd, boolean isWrite){
+  if (isWrite)
+  {
+    command(SPIFLASH_WRITEENABLE); // Write Enable
+    unselect();
+  }
+  while(busy()); //wait for any write/erase to complete
+  select();
+  SPI.transfer(cmd);
+}
+
+/// check if the chip is busy erasing/writing
+boolean SPIFlash::busy()
+{
+  /*
+  select();
+  SPI.transfer(SPIFLASH_STATUSREAD);
+  byte status = SPI.transfer(0);
+  unselect();
+  return status & 1;
+  */
+  return readStatus() & 1;
+}
+
+/// return the STATUS register
+byte SPIFlash::readStatus()
+{
+  select();
+  SPI.transfer(SPIFLASH_STATUSREAD);
+  byte status = SPI.transfer(0);
+  unselect();
+  return status;
+}
+
+
+/// Write 1 byte to flash memory
+/// WARNING: you can only write to previously erased memory locations (see datasheet)
+///          use the block erase commands to first clear memory (write 0xFFs)
+void SPIFlash::writeByte(long addr, uint8_t byt) {
+  command(SPIFLASH_BYTEPAGEPROGRAM, true);  // Byte/Page Program
+  SPI.transfer(addr >> 16);
+  SPI.transfer(addr >> 8);
+  SPI.transfer(addr);
+  SPI.transfer(byt);
+  unselect();
+}
+
+/// write 1-256 bytes to flash memory
+/// WARNING: you can only write to previously erased memory locations (see datasheet)
+///          use the block erase commands to first clear memory (write 0xFFs)
+/// WARNING: if you write beyond a page boundary (or more than 256bytes),
+///          the bytes will wrap around and start overwriting at the beginning of that same page
+///          see datasheet for more details
+void SPIFlash::writeBytes(long addr, const void* buf, uint8_t len) {
+  command(SPIFLASH_BYTEPAGEPROGRAM, true);  // Byte/Page Program
+  SPI.transfer(addr >> 16);
+  SPI.transfer(addr >> 8);
+  SPI.transfer(addr);
+  for (uint8_t i = 0; i < len; i++)
+    SPI.transfer(((byte*) buf)[i]);
+  unselect();
+}
+
+/// erase entire flash memory array
+/// may take several seconds depending on size, but is non blocking
+/// so you may wait for this to complete using busy() or continue doing
+/// other things and later check if the chip is done with busy()
+/// note that any command will first wait for chip to become available using busy()
+/// so no need to do that twice
+void SPIFlash::chipErase() {
+  command(SPIFLASH_CHIPERASE, true);
+  unselect();
+}
+
+/// erase a 4Kbyte block
+void SPIFlash::blockErase4K(long addr) {
+  command(SPIFLASH_BLOCKERASE_4K, true); // Block Erase
+  SPI.transfer(addr >> 16);
+  SPI.transfer(addr >> 8);
+  SPI.transfer(addr);
+  unselect();
+}
+
+/// erase a 32Kbyte block
+void SPIFlash::blockErase32K(long addr) {
+  command(SPIFLASH_BLOCKERASE_32K, true); // Block Erase
+  SPI.transfer(addr >> 16);
+  SPI.transfer(addr >> 8);
+  SPI.transfer(addr);
+  unselect();
+}
+
+/// cleanup
+void SPIFlash::end() {
+  SPI.end();
+}