Dwayne Dilbeck / Mbed 2 deprecated Max7221

A generic library to support Max7221 chip for 8 digit 7 segment displays

Dependencies:   mbed

Dependents:   Example_Max7221

MAXIM SPI interfaced, 8 digit LED display Driver

MAX221

  • The image below was my initial development setup. The top of the image shows a wire wrap connection to a Max7221 to an 8 digit 7 segment display.
  • The small board below it is the new max7221 board that was created with surface mount chips and using a toaster oven to do reflow soldering. /media/uploads/jakowisp/img_0012.jpg

Example of using a single Max7221 on SPI p5,p6,p7

Import program
Example_Max7221 - main.cpp

00001  #include "mbed.h"
00002  #include "Max7221.h"
00003  
00004 
00005 // p5: DIN, p7: CLK, p8: LOAD/CS
00006 Max7221 max7221disp1(p5, p7, p8);
00007 //Max7221 max7221disp2(p5, p7, p8);
00008 //Max7221 max7221disp3(p11, p13, p14);
00009 //Max7221 max7221disp4(p11, p13, p14);
00010 
00011 int count=-99;
00012 
00013 void loop(void) {
00014    max7221disp1=count;
00015    if (count < 100)
00016       count=count+1;
00017    else 
00018       count=-99; 
00019 }
00020 
00021 int main() {  
00022     max7221disp1.Setup();
00023     //Max7221::SetupALl();
00024     max7221disp1.WriteFloat(123.125);
00025     wait(1.0);  
00026 
00027     while (1) {
00028         loop();
00029         wait(1.0);
00030     }
00031 }
00032 
00033

Files at this revision

API Documentation at this revision

Revision 4:e2b160410338, committed 2013-08-07

Comitter:
jakowisp
Date:
Wed Aug 07 03:07:01 2013 +0000
Parent:
3:5abc4047af8d
Commit message:
Correct the Doxygen generation for the class.

Changed in this revision

Max7221.h Show annotated file Show diff for this revision Revisions of this file 
diff -r 5abc4047af8d -r e2b160410338 Max7221.h
--- a/Max7221.h	Wed Aug 07 02:34:59 2013 +0000
+++ b/Max7221.h	Wed Aug 07 03:07:01 2013 +0000
@@ -10,7 +10,35 @@
 #ifndef Max7221_H
 #define Max7221_H
 
-/** Max7221 Example
+
+// define max7219/max7221 registers
+#define max7219_reg_noop         0x00
+#define max7219_reg_digit0       0x01
+#define max7219_reg_digit1       0x02
+#define max7219_reg_digit2       0x03
+#define max7219_reg_digit3       0x04
+#define max7219_reg_digit4       0x05
+#define max7219_reg_digit5       0x06
+#define max7219_reg_digit6       0x07
+#define max7219_reg_digit7       0x08
+#define max7219_reg_decodeMode   0x09
+#define max7219_reg_intensity    0x0a
+#define max7219_reg_scanLimit    0x0b
+#define max7219_reg_shutdown     0x0c
+#define max7219_reg_displayTest  0x0f
+
+#define LOW 0
+#define HIGH 1
+#define MHZ 1000000
+#define NUMDIGITS 8
+
+#ifdef NUMDIGITS 
+#define UPPERBOUND 99999999
+#define LOWERBOUND -9999999
+#endif
+
+/**
+ * Max7221 Example
  * @code
  * #include "mbed.h"
  * #include "Max7221.h"
@@ -45,117 +73,89 @@
  * }
  * @endcode
  */
-
-// define max7219/max7221 registers
-#define max7219_reg_noop         0x00
-#define max7219_reg_digit0       0x01
-#define max7219_reg_digit1       0x02
-#define max7219_reg_digit2       0x03
-#define max7219_reg_digit3       0x04
-#define max7219_reg_digit4       0x05
-#define max7219_reg_digit5       0x06
-#define max7219_reg_digit6       0x07
-#define max7219_reg_digit7       0x08
-#define max7219_reg_decodeMode   0x09
-#define max7219_reg_intensity    0x0a
-#define max7219_reg_scanLimit    0x0b
-#define max7219_reg_shutdown     0x0c
-#define max7219_reg_displayTest  0x0f
-
-#define LOW 0
-#define HIGH 1
-#define MHZ 1000000
-#define NUMDIGITS 8
-
-#ifdef NUMDIGITS 
-#define UPPERBOUND 99999999
-#define LOWERBOUND -9999999
-#endif
-
 class Max7221 {
 public:
-/**
-*  Constructor. This is the default constructor
-*  @author Dwayne S. Dilbeck
-*  @param msoi  The SPI pin used as input to the device.       Valid values for LPC1768 are p5 or p11
-*  @param mclk  The SPI pin used as clock for the device.      Valid values for LPC1768 are p7 or p13
-*  @param load  The pin used to control load for the device.   Any pin capable for DigitalOut can be used, but the same load pin must be used for 
-*    device that share the same msoi and mclk pins
-*  @date 8/6/2013
-*/
-   Max7221(PinName msoi=p5, PinName mclk=p7, PinName load=p8);
+    /**
+    *  Constructor. This is the default constructor
+    *  @author Dwayne S. Dilbeck
+    *  @param msoi  The SPI pin used as input to the device.       Valid values for LPC1768 are p5 or p11
+    *  @param mclk  The SPI pin used as clock for the device.      Valid values for LPC1768 are p7 or p13
+    *  @param load  The pin used to control load for the device.   Any pin capable for DigitalOut can be used, but the same load pin must be used for 
+    *    device that share the same msoi and mclk pins
+    *  @date 8/6/2013
+    */
+    Max7221(PinName msoi=p5, PinName mclk=p7, PinName load=p8);
    
-/**
-*  This method is used to write a byte of data to a specified register for only the device defined in this class instance
-*  @author Dwayne S. Dilbeck
-*  @param reg  The register to write to.
-*  @param data The value to be written.
-*  @date 8/6/2013   
-*/
-   void Write( unsigned int reg, unsigned int data);
+    /**
+    *  This method is used to write a byte of data to a specified register for only the device defined in this class instance
+    *  @author Dwayne S. Dilbeck
+    *  @param reg  The register to write to.
+    *  @param data The value to be written.
+    *  @date 8/6/2013   
+    */
+    void Write( unsigned int reg, unsigned int data);
 
-/**
-*  This method is used to display an integer to the specified device instance. Underflow and overflow result in '-' written to all digits
-*  @author Dwayne S. Dilbeck
-*  @param value  An integer value to display
-*  @date 8/6/2013   
-*/   
-   void WriteInt( int value );
+    /**
+    *  This method is used to display an integer to the specified device instance. Underflow and overflow result in '-' written to all digits
+    *  @author Dwayne S. Dilbeck
+    *  @param value  An integer value to display
+    *  @date 8/6/2013   
+    */   
+    void WriteInt( int value );
 
-/**
-*  This method is used to display a floating point number to the specified device instance. 
-*   Underflow and overflow result in '-' written to all digits. The digits after the decimal 
-*   point are truncated to fit the display.
-*  @author Dwayne S. Dilbeck
-*  @param value  A float value to display
-*  @date 8/6/2013   
-*/   
-   void WriteFloat( float value);
+    /**
+    *  This method is used to display a floating point number to the specified device instance. 
+    *   Underflow and overflow result in '-' written to all digits. The digits after the decimal 
+    *   point are truncated to fit the display.
+    *  @author Dwayne S. Dilbeck
+    *  @param value  A float value to display
+    *  @date 8/6/2013   
+    */   
+    void WriteFloat( float value);
    
-/**
-*  Overload of the EQUALS operator to provide easy use of the class.
-*  @author Dwayne S. Dilbeck
-*  @param value  An integer value to display
-*  @date 8/6/2013   
-*/   
-   
-   Max7221& operator= (int value){ 
+    /**
+    *  Overload of the EQUALS operator to provide easy use of the class.
+    *  @author Dwayne S. Dilbeck
+    *  @param value  An integer value to display
+    *  @date 8/6/2013   
+    */      
+    Max7221& operator= (int value){ 
         WriteInt(value); 
         return *this;
         };
-/**
-*  Overload of the EQUALS operator to provide easy use of the class.
-*  @author Dwayne S. Dilbeck
-*  @param value  A float value to display
-*  @date 8/6/2013   
-*/   
-
-   Max7221& operator= (float value){ 
+    /**
+    *  Overload of the EQUALS operator to provide easy use of the class.
+    *  @author Dwayne S. Dilbeck
+    *  @param value  A float value to display
+    *  @date 8/6/2013   
+    */   
+    Max7221& operator= (float value){ 
         WriteFloat(value); 
         return *this; 
         };
-/**
-*  This method is used to write an  intial set off values to the device to prepare it for use.
-*  @author Dwayne S. Dilbeck
-*  @date 8/6/2013   
-*/   
-   void Setup (void);
+
+    /**
+    *  This method is used to write an  intial set off values to the device to prepare it for use.
+    *  @author Dwayne S. Dilbeck
+    *  @date 8/6/2013   
+    */   
+    void Setup (void);
 
-/**
-*  This method is used to write a byte of data to a specified register for all the devices instantiated.
-*  @author Dwayne S. Dilbeck
-*  @param reg  The register to write to.
-*  @param data The value to be written.
-*  @date 8/6/2013   
-*/   
-   static void WriteAll (unsigned int reg, unsigned int data);
+    /**
+    *  This method is used to write a byte of data to a specified register for all the devices instantiated.
+    *  @author Dwayne S. Dilbeck
+    *  @param reg  The register to write to.
+    *  @param data The value to be written.
+    *  @date 8/6/2013   
+    */   
+    static void WriteAll (unsigned int reg, unsigned int data);
 
-/**
-*  This method is used to write an intial set off values to ALL device to prepare them for use.
-*  @author Dwayne S. Dilbeck
-*  @date 8/6/2013   
-*/   
-   static void SetupAll (void);
+    /**
+    *  This method is used to write an intial set off values to ALL device to prepare them for use.
+    *  @author Dwayne S. Dilbeck
+    *  @date 8/6/2013   
+    */   
+    static void SetupAll (void);
    
 private:
    /// Pointer for the class instance to a particular SPI bus