first commit

SpiRAM.cpp

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+/*
+ * SpiRAM.cpp - Library for driving a 23k256 SPI attached SRAM chip
+ *
+ * Phil Stewart, 18/10/2009
+ * 
+ * Copyright (c) 2009, Phil Stewart
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *  
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *             
+ */
+/*
+ * Updated to Arduino 1.0.5 and newer version of SPI 
+ * "2010 by Cristian Maglie"
+ * by Fred Jan Kraan, fjkraan@xs4all.nl, 2014-02-28
+ */ 
+
+#include <SPI.h>
+#include <SpiRAM.h>
+
+// Constructor
+
+SpiRAM::SpiRAM(SPIClass &spi, byte ssPin): _spi(spi)
+{
+  _ssPin = ssPin;
+
+  // Set the RAM operarion mode flag according to the chip default
+  _current_mode = BYTE_MODE;
+}
+
+// Enable and disable helper functions
+
+void SpiRAM::enable()
+{
+  digitalWrite(_ssPin, LOW);
+}
+
+void SpiRAM::disable()
+{
+  digitalWrite(_ssPin, HIGH);
+}
+
+// Byte transfer functions
+
+char SpiRAM::read_byte(int address)
+{
+  char read_byte;
+
+  // Set byte mode
+  _set_mode(BYTE_MODE);
+
+  // Write address, read data
+  enable();
+  _spi.transfer(READ);
+  _spi.transfer((char)(address >> 8));
+  _spi.transfer((char)address);
+  read_byte = _spi.transfer(0xFF);
+  disable();
+
+  return read_byte;
+}
+
+char SpiRAM::write_byte(int address, char data_byte)
+{
+  // Set byte mode
+  _set_mode(BYTE_MODE);
+
+  // Write address, read data
+  enable();
+  _spi.transfer(WRITE);
+  _spi.transfer((char)(address >> 8));
+  _spi.transfer((char)address);
+  _spi.transfer(data_byte);
+  disable();
+
+  return data_byte;
+}
+
+// Page transfer functions. Bound to current page. Passing the boundary 
+//  will wrap to the beginning
+void SpiRAM::read_page(int address, char *buffer)
+{
+  int i;
+
+  // Set byte mode
+  _set_mode(PAGE_MODE);
+
+  // Write address, read data
+  enable();
+  _spi.transfer(READ);
+  _spi.transfer((char)(address >> 8));
+  _spi.transfer((char)address);
+  for (i = 0; i < 32; i++) {
+    buffer[i] = _spi.transfer(0xFF);
+  }    
+  disable();
+}
+
+void SpiRAM::write_page(int address, char *buffer)
+{
+  int i;
+
+  // Set byte mode
+  _set_mode(PAGE_MODE);
+
+  // Write address, read data
+  enable();
+  _spi.transfer(WRITE);
+  _spi.transfer((char)(address >> 8));
+  _spi.transfer((char)address);
+  for (i = 0; i < 32; i++) {
+    _spi.transfer(buffer[i]);
+  }    
+  disable();
+}
+
+// Stream transfer functions. Ignores page boundaries.
+void SpiRAM::read_stream(int address, char *buffer, int length)
+{
+  int i;
+
+  // Set byte mode
+  _set_mode(STREAM_MODE);
+
+  // Write address, read data
+  enable();
+  _spi.transfer(READ);
+  _spi.transfer((char)(address >> 8));
+  _spi.transfer((char)address);
+  for (i = 0; i < length; i++) {
+    buffer[i] = _spi.transfer(0xFF);
+  }    
+  disable();
+}
+
+void SpiRAM::write_stream(int address, char *buffer, int length)
+{
+  int i;
+
+  // Set byte mode
+  _set_mode(STREAM_MODE);
+
+  // Write address, read data
+  enable();
+  _spi.transfer(WRITE);
+  _spi.transfer((char)(address >> 8));
+  _spi.transfer((char)address);
+  for (i = 0; i < length; i++) {
+    _spi.transfer(buffer[i]);
+  }    
+  disable();
+}
+
+
+// Mode handling
+void SpiRAM::_set_mode(char mode)
+{
+  if (mode != _current_mode)
+  {
+    enable();
+    _spi.transfer(WRSR);
+    _spi.transfer(mode);
+    disable();
+    _current_mode = mode;
+  }
+}

SpiRAM.h

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+/*
+ * SpiRAM.h - Library for driving a 23k256 SPI attached SRAM chip
+ *
+ * Phil Stewart, 18/10/2009
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ *  
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR   
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,  
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR   
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING  
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS    
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef SpiRAM_h
+#define SpiRAM_h
+
+#define SPIRAM_LIB_VERSION  "0.3.00"
+
+#include <Arduino.h>
+#include <SPI.h>
+
+// SRAM opcodes
+// #define WREN  6
+// #define WRDI  4
+#define RDSR  5
+#define WRSR  1
+#define READ  3
+#define WRITE 2
+
+// SRAM Hold line override
+#define HOLD 1
+
+// SRAM modes
+#define BYTE_MODE (0x00 | HOLD)
+#define PAGE_MODE (0x80 | HOLD)
+#define STREAM_MODE (0x40 | HOLD)
+
+// Clock speeds
+#define RAMCLK4M   0
+#define RAMCLK1M   1
+#define RAMCLK250K 2
+#define RAMCLK125K 3
+
+class SpiRAM
+{
+  public:
+    SpiRAM(SPIClass &spi, byte ssPin);
+    void enable();
+    void disable();
+    char read_byte(int address);
+    char write_byte(int address, char data_byte);
+    void read_page(int address, char *buffer);
+    void write_page(int address, char *buffer);
+    void read_stream(int address, char *buffer, int length);
+    void write_stream(int address, char *buffer, int length);
+  private:
+    char _current_mode;
+    byte _ssPin;
+    void _set_mode(char mode); 
+    SPIClass &_spi;
+};
+
+extern SpiRAM SpiRam;
+
+#endif 

example/SpiRAM_Example/SpiRAM_Example.ino

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+#include <SPI.h>
+#include <SpiRAM.h>
+
+#define SS_PIN 10
+
+byte clock = 0;
+SpiRAM SpiRam(0, SS_PIN);
+
+void setup()   {                
+  Serial.begin(9600);
+}
+
+void loop()                    
+{
+  char data_to_chip[17] = "Testing 90123456";
+  char data_from_chip[17] = "                ";
+  int i = 0;
+
+  // Write some data to RAM
+  SpiRam.write_stream(0, data_to_chip, 16);
+  delay(100);
+
+  // Read it back to a different buffer
+  SpiRam.read_stream(0, data_from_chip, 16);
+
+  // Write it to the serial port
+  for (i = 0; i < 16; i++) {
+    Serial.print(data_from_chip[i]);
+  }
+  Serial.print("\n");
+  delay(1000);                  // wait for a second
+}

example/spiRamTest.ino

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+
+#include <SPI.h>
+#include <SpiRAM.h>
+
+#define SS_PIN 10
+
+byte clock = 0;
+SpiRAM spiRam(0, SS_PIN);
+
+void setup() {
+
+  Serial.begin(115200);     // writing a byte is ~ 86 uS at 115200 Baud
+  delay(1000);              // wait for a second
+  Serial.println("Versie 1");  
+}
+
+void loop() {
+  unsigned long address = 0;
+
+}

example/spiRamTest/spiRamTest.ino

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+
+#include <SPI.h>
+#include <SpiRAM.h>
+
+#define SS_PIN 10
+
+byte clock = 0;
+SpiRAM spiRam(0, SS_PIN);
+
+void setup() {
+  digitalWrite(A5, HIGH);
+  Serial.begin(115200); 
+  delay(1000);              // wait for a second
+  Serial.println("Version 1");  
+}
+
+// The RAM, initially having random contents, will fail the test. If A5 is 
+// pulled to ground, the correct value will be written before test, and the
+// RAM location written to, will pass the test. Keeping A5 low for the full 
+// cycle from 0 to 7FFF will make the test completely happy. Until the next
+// next power cycle.
+void loop() {
+  unsigned int address = 0;
+  unsigned int i;
+  unsigned int maxRam = 32768;
+  byte wValue, rValue;
+  for (i=0; i < maxRam; i++) {
+    wValue = (byte) (i & 0xFF);
+    if (digitalRead(A5) == LOW) {
+      spiRam.write_byte(i, wValue);
+    }
+    rValue = (byte)spiRam.read_byte(i);
+    if (wValue != rValue) {
+      Serial.print("RAM error at ");
+      Serial.print(i, HEX);
+      Serial.print(" should be ");
+      Serial.print(wValue, HEX);
+      Serial.print(" is ");
+      Serial.println(rValue, HEX);
+    } else {
+      Serial.println(i, HEX);
+    }
+  }
+}