+// $Id$
+
+/*
+ *
+ *
+ * "Copyright (c) 2000-2005 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for any purpose, without fee, and without written agreement is
+ * hereby granted, provided that the above copyright notice, the following
+ * two paragraphs and the author appear in all copies of this software.
+ *
+ * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
+ * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
+ * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS."
+ *
+ */
+
+/**
+ * @author Jonathan Hui <jwhui@cs.berkeley.edu>
+ * @author Roland Flury <roland.flury@shockfish.com>
+ */
+
+module ExtFlashC {
+ provides {
+ interface Init;
+ interface StdControl;
+ interface ExtFlash;
+ }
+}
+
+/**
+ * Simple reader module to access the Atmel at45db041 flash chip
+ */
+implementation {
+
+ uint32_t addr;
+
+ command error_t Init.init() {
+
+ TOSH_SET_FLASH_CS_PIN(); // inverted, deselect by default
+ TOSH_MAKE_FLASH_CS_OUTPUT();
+
+ TOSH_CLR_FLASH_CLK_PIN();
+ TOSH_MAKE_FLASH_CLK_OUTPUT();
+
+ TOSH_SET_FLASH_OUT_PIN();
+ TOSH_MAKE_FLASH_OUT_OUTPUT();
+
+ TOSH_MAKE_FLASH_IN_INPUT();
+
+ TOSH_SET_FLASH_RESET_PIN(); // inverted
+ TOSH_MAKE_FLASH_RESET_OUTPUT();
+
+ return SUCCESS;
+ }
+
+ command error_t StdControl.start() { return SUCCESS; }
+ command error_t StdControl.stop() { return SUCCESS; }
+
+ /**
+ * Write a Byte over the SPI bus and receive a Byte
+ *
+ * upon calling this function, /CS must be CLR
+ */
+ uint8_t SPIByte(uint8_t out) {
+ uint8_t in = 0;
+ uint8_t i;
+
+ for ( i = 0; i < 8; i++, out <<= 1 ) {
+ // write bit
+ if (out & 0x80) {
+ TOSH_SET_FLASH_OUT_PIN();
+ } else {
+ TOSH_CLR_FLASH_OUT_PIN();
+ }
+
+ // clock
+ TOSH_SET_FLASH_CLK_PIN();
+
+ // read bit
+ in <<= 1;
+ if (TOSH_READ_FLASH_IN_PIN()) {
+ in |= 1;
+ }
+
+ // clock
+ TOSH_CLR_FLASH_CLK_PIN();
+ }
+
+ return in;
+ }
+
+
+
+ /**
+ * Initializes the flash to read Byte after Byte starting
+ * from the given address.
+ *
+ * Subsequent calls to readByte() will return the Bytes
+ * starting from the specified address.
+ *
+ * stopRead() terminates this process and disables the Flash.
+ */
+ command void ExtFlash.startRead(uint32_t newAddr) {
+ uint8_t cmdBuf[4];
+ uint8_t i;
+
+ // we're using "Waveform 1 - Inactive Clock Polarity Low"
+ // see p.7 of data sheet
+ TOSH_CLR_FLASH_CLK_PIN();
+ TOSH_CLR_FLASH_CS_PIN(); // select the flash
+
+ addr = newAddr;
+
+ // we only use 256 Bytes per block (of 264 Bytes)
+ cmdBuf[0] = 0x52; // command for reading data starting at the following address
+ cmdBuf[1] = (addr >> 15) & 0xff; // 4 LSbits
+ cmdBuf[2] = (addr >> 7) & 0xfe; // 7 MSbits with the above 4 bits describe page to read
+ cmdBuf[3] = addr & 0xff; // Offset to Byte in page to read
+
+ // transmit read command
+ for(i = 0; i < 4; i++) {
+ SPIByte(cmdBuf[i]);
+ }
+ // transmit 4 Bytes "don't care" as to spec
+ for(i = 0; i < 4; i++) {
+ SPIByte(0x0);
+ }
+
+ // need to do one additional clock transition before reading
+ TOSH_SET_FLASH_CLK_PIN();
+ TOSH_CLR_FLASH_CLK_PIN();
+ }
+
+ command uint8_t ExtFlash.readByte() {
+ uint8_t b = SPIByte(0); // write anything, read Byte
+ addr++;
+ if(0 == (addr & 0xFF)) {
+ // we've just read the last Byte from a page
+ // initialize the Flash to continue reading on the new page
+ call ExtFlash.stopRead();
+ call ExtFlash.startRead(addr);
+ }
+ return b;
+ }
+
+ command void ExtFlash.stopRead() {
+ TOSH_SET_FLASH_CS_PIN(); // disble Flash & tri-state the OUT-pin
+ }
+
+}