Revision 7:a160cb7cdd86, committed 2015-11-23

Comitter:

ky3orr

Date:

Mon Nov 23 11:28:44 2015 +0000

Parent:

6:191569a26f50

Child:

8:3f5901f2f813

Commit message:

Code refactored to have MAX7219/7221 driver only with SPI chain support.

Changed in this revision

--- a/Max7221.cpp	Thu Nov 19 23:58:07 2015 +0000
+++ b/Max7221.cpp	Mon Nov 23 11:28:44 2015 +0000
@@ -1,230 +1,105 @@
 /**
 * @file Max7221.cpp
-* @brief This file defines the Max7221 class methods and the default values for static variables
+* @brief MAX7219/7221 driver class.
 * 
-* @author Dwayne S. Dilbeck
-*
-* @date 8/6/2013
+* @author Grzegorz Kaczmarek
+* @comment Code inspired on erlier Dwayne S. Dilbeck's work
+* @date 20/11/2015
 */
+
 #include "mbed.h"
 #include "Max7221.h"
 
-///Intialize the Class static members
-///Devices used per SPI bus are set to ZERO
-int Max7221::maxInUseSPI = 0;
-///Set the static pointers to the SPI busses to NULL
-SPI *Max7221::spi=NULL;
-///Set the static pointers to the load signals to NULL
-DigitalOut *Max7221::cs=NULL;
-
-/**
-*  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::Max7221(PinName msoi, PinName mclk, PinName load){
-  ///Set this insctance to pointers to the correct static pointers
-  this->id=maxInUseSPI;
-  this->maxInUse=&maxInUseSPI;
-  ///If no devices have been assigned to the SPI bus it must be initialized
-  if (spi ==NULL) {
-     spi = new SPI(msoi, NC, mclk);
-     cs = new DigitalOut(load);
-  }
-  this->max7221_spi= spi;
-  this->max7221_cs = cs;
+Max7221::Max7221(SPI *spi, DigitalOut *cs, unsigned int position) :
+    mp_spi(spi),
+    mp_cs(cs),
+    m_position(position)
+{
 }
 
-/**
-*  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   
-*//**
-*  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 Max7221::Write( unsigned int reg, unsigned int data) {
-    int c = 0;
-    *cs = LOW;
-
-    ///if there are multiple devices sharing the SPI buss and they preceed the current device in the cascade Write a NOOP to them
-    for ( c = *maxInUse; c > this->id; c--) {
-        max7221_spi->write(0);  // no-op
-        max7221_spi->write(0);  // no-op
+void Max7221::CsLow()
+{
+    if(mp_cs != NULL) {
+        *mp_cs = LOG_0;
     }
-    ///Write to this device registers
-    max7221_spi->write(reg);  // specify register
-    max7221_spi->write(data);  // put data
-
-    ///if there are multiple devices sharing the SPI buss and they follow the current device in the cascade Write a NOOP to them
-    for ( c=this->id-1; c >= 1; c--) {
-        max7221_spi->write(0);  // no-op
-        max7221_spi->write(0);  // no-op
-    }
-    *cs = HIGH;
 }
 
-/**
-*  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 Max7221::Setup () {
-    // initiation of the max 7221
-    // SPI setup: 8 bits, mode 0
-    max7221_spi->format(8, 0);
-    
-    // going by the datasheet, min clk is 100ns so theoretically 10MHz should work...
-    max7221_spi->frequency(10*MHZ);
-    
-    Write(max7219_reg_scanLimit, 0x07);   ///ENABLE all 8 digits
-    Write(max7219_reg_decodeMode, 0xff);  // Turn on Code B font decode for all digits
-    Write(max7219_reg_shutdown, 0x01);    // Disable shutdown mode
-    Write(max7219_reg_displayTest, 0x00); // Disable display test
-    for (int e=1; e<=8; e++) {            // Write blank to all digits
-        Write(e,0xf);
+void Max7221::CsHigh()
+{
+    if(mp_cs != NULL) {
+        *mp_cs = LOG_1;
     }
-    Write(max7219_reg_intensity, 0x01 );    // Set the display intensity to a low level. 
-                                                  // range: 0x00 to 0x0f
 }
 
-/**
-*  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   
-*/   
-void Max7221::WriteAll (unsigned int reg, unsigned int data) {   
-    ///Write to all the devices on SPI Bus #1 first
-    if(cs !=NULL) {
-        *cs = LOW;                    // begin
-        for ( int c=1; c<= maxInUseSPI; c++) {
-            spi->write(reg);  // specify register
-            spi->write(data);  // put data
-        }
-        *cs = HIGH;
+void Max7221::WriteRaw(unsigned int reg, unsigned int data) {
+    if(mp_spi != NULL) {
+        mp_spi->write(reg);
+        mp_spi->write(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 Max7221::WriteInt( int value ){
-  char buffer[16];
-   
-  ///TODO:SET UPPERBOUND AND LOWERBOUND based on NUMDIGITS
-  ///Check the the INT value can be displayed and convert to a string.
-  if (value <= UPPERBOUND && value >= LOWERBOUND) {
-     sprintf(buffer,"%8d",value);
-  } else {
-     sprintf(buffer,"--------");
-  } 
-  ///In case a program changed the decode mode, set it again.
-  Write(max7219_reg_decodeMode, 0xff);
-  for (int i=0;i<NUMDIGITS;i++) {
-       ///For each character of the string, convert the ASCII to the datacode needed by the device
-       switch(buffer[i]){
-           case 0x2d: buffer[i]=0xa; break;
-           case 0x20: buffer[i]=0xf; break;
-           default: buffer[i]= buffer[i] & 0x0f;
-       }
-       ///Call function to write the data for each character of the srting.
-       Write(NUMDIGITS-i,buffer[i]);
-  }
+
+void Max7221::Write(unsigned int reg, unsigned int data) {
+    unsigned int i;
+    
+    CsLow();
+    WriteRaw(reg, data);
+    if(m_position > 0) {
+        i = m_position;
+        while(i--) {
+            WriteRaw(max7219_reg_noop, 0x0);
+        }
+    }
+    CsHigh();
+}
+
+void Max7221::TestMode(bool mode) {
+    if(mode) {
+        Write(max7219_reg_displayTest, 0x01);
+    } else {
+        Write(max7219_reg_displayTest, 0x00);
+    }
+}
+
+void Max7221::UseDigitsNo(unsigned int digits_no) {
+    if((digits_no > 0) && (digits_no < 9)) {
+        Write(max7219_reg_scanLimit, (digits_no - 1));
+    }
+}
+
+void Max7221::DecodeMode(unsigned int mode) {
+    Write(max7219_reg_decodeMode, mode);
 }
 
-/**
-*  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 Max7221::WriteFloat( float value ){
-  char buffer[32];
-  int ptr=-1,len;
-  int i;
- 
-  sprintf(buffer,"%f",value);
-  len=strlen(buffer);
-  i=len-1;
-  while(buffer[i]==0x30) {
-     buffer[i]='\0';
-     i--;
-     len--;
-  }
-  for( i =0; i<=len; i++) {
-      switch(buffer[i]){
-               case 0x2d: buffer[i]=0xa; break;
-               case 0x20: buffer[i]=0xf; break;
-               case 0x2e: buffer[i]=buffer[i-1] | 0x80;
-                           ptr = i-1;
-                           break;
-               default: buffer[i]= buffer[i];
-      }       
-      if (ptr != -1) {
-        buffer[i-1]=buffer[i]; 
-     }
-  }
-     
-  len=strlen(buffer);
-  Write(max7219_reg_decodeMode, 0xff);
+void Max7221::WriteDigit(unsigned int digit_no, unsigned int value) {
+    if(digit_no < 8) {
+        Write(digit_no, value);
+    }
+}
 
-  // If too large for display set to '-'
-  if(len > NUMDIGITS && (ptr==-1 || ptr>NUMDIGITS))
-        for (int i=0;i<NUMDIGITS;i++) {
-           buffer[i]=0x0a;
-        }
-  //if number is smaller than display, fill with ' '      
-  if (len<=NUMDIGITS) { 
-      for (int i=1;i<=NUMDIGITS;i++) {
-           if(len-i>=0) {
-             Write(i,buffer[len-i]);
-           } else {
-             Write(i,0xf);   
-           }
-      }
-  } else {
-  //Write out the buffer, truncating the decimal digits if larger than display
-      for (int i=0;i<NUMDIGITS;i++) {
-          Write(NUMDIGITS-i,buffer[i]);
-      }
-  }
+void Max7221::Intensity(unsigned int intensity) {
+    if(intensity > 0x0F) {
+        intensity = 0x0F;
+    }
+    Write(max7219_reg_intensity, intensity);
 }
 
-/**
-*  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   
-*/   
-void Max7221::SetupAll () {
-    // initiation of the max 7219
-    // SPI setup: 8 bits, mode 0
-    if(spi!=NULL) {
-       spi->format(8, 0);
-       spi->frequency(10*MHZ);    
-    }               
-    WriteAll(max7219_reg_scanLimit, 0x07);
-    WriteAll(max7219_reg_decodeMode, 0xff);  // using an led matrix (not digits)
-    WriteAll(max7219_reg_shutdown, 0x01);    // not in shutdown mode
-    WriteAll(max7219_reg_displayTest, 0x00); // no display test
-    for (int e=1; e<=8; e++) {            // empty registers, turn all LEDs off
-        WriteAll(e,0xf);
+void Max7221::OperationMode(bool mode) {
+    if(mode) {
+        Write(max7219_reg_shutdown, 0x01);
+    } else {
+        Write(max7219_reg_shutdown, 0x00);
     }
-    WriteAll(max7219_reg_intensity, 0x01 & 0x0f);    // the first 0x0f is the value you can set
-                                                  // range: 0x00 to 0x0f
 }
 
+void Max7221::Setup () {
+    unsigned int i;
+
+    TestMode(false);            // Disable display test
+    UseDigitsNo(8);             // Use all 8 digits
+    DecodeMode(0xFF);           // Turn on Code B font decode for all digits
+    for(i=1;i<9;i++) {          // Clean all digits
+        WriteDigit(i, 0x0F);
+    }
+    Intensity(0x01);            // Set lowest display intensity(0x00-0xFF)
+    OperationMode(true);        // Enable operation mode
+}

--- a/Max7221.h	Thu Nov 19 23:58:07 2015 +0000
+++ b/Max7221.h	Mon Nov 23 11:28:44 2015 +0000
@@ -1,179 +1,108 @@
 /**
 * @file Max7221.h
-* @brief This file contains the class defnition of Max7221 and define statements related to the class, and max7221 device
-* The methods in this class are derived from posts on the mbed forum written by Igor Skochinsky on October 2009
+* @brief Header file for the MAX7219/7221 driver class.
 * 
-* @author Dwayne S. Dilbeck
-*
-* @date 8/6/2013
+* @author Grzegorz Kaczmarek
+* @comment Code inspired on erlier Dwayne S. Dilbeck's work
+* @date 20/11/2015
 */
+
 #ifndef Max7221_H
 #define Max7221_H
 
-
-// define max7219/max7221 registers
+// MAX7219/7221 register map
 #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
+// Logical values
+#define LOG_0 0
+#define LOG_1 1
 
-/**
- * Max7221 Example
- * @code
- * #include "mbed.h"
- * #include "Max7221.h"
- *  
- * 
- * // p5: DIN, p7: CLK, p8: LOAD/CS
- * Max7221 max7221disp1(p5, p7, p8);
- * //Max7221 max7221disp2(p5, p7, p8);
- * //Max7221 max7221disp3(p11, p13, p14);
- * //Max7221 max7221disp4(p11, p13, p14);
- * 
- * int count=-99;
- * 
- * void loop(void) {
- *    max7221disp1.WriteInt(count);
- *    if (count < 100)
- *       count=count+1;
- *    else 
- *      count=-99; 
- * }
- * 
- * int main() {  
- *     max7221disp1.Setup();
- *     //Max7221::SetupALl();
- *     max7221disp1.WriteFloat(123.125);
- *     wait(1.0);  
- * 
- *     while (1) {
- *         loop(); 
- *         wait(1.0);
- *     }
- * }
- * @endcode
- */
 class Max7221 {
+private:
+   SPI *mp_spi;             // SPI used for this display (no data transmission when NULL)
+   DigitalOut *mp_cs;       // CS signal (it should be handled manually when NULL)
+   unsigned int m_position; // Display position on SPI chain (0 = 1'st)
+
 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
+    *  Default constructor.
+    *  @param spi       Initialized SPI port used for communication with MAX7219/7221.
+    *  @param cs        Initialized output pin used as SW CS signal or NULL when HW one is used.
+    *  @param position  Position on SPI port (for displays connected in daisy-chain: DOUT-DIN). 0=1st.
+    */
+    Max7221(SPI *spi, DigitalOut *cs, unsigned int position=0);
+
+    /**
+    *  Method for setting /CS signal LOW (enable data reception).
     */
-    Max7221(PinName msoi=PTC6, PinName mclk=PTC5, PinName load=PTC4);
+    void CsLow(void);
+
+    /**
+    *  Method for setting /CS signal HIGH (received data is latched and processed).
+    */
+    void CsHigh(void);
+
+    /**
+    *  Method used to send data over SPI (no use of /CS signal).
+    *  To be used with display chains and when building display libraries
+    *  where amount of data needs to be pushed via SPI in one transaction.
+    */
+    void WriteRaw(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   
+    *  Method for sending register-value pair for this diasplay.
+    *  Supports display chain on single SPI (m_position > 0).
     */
-    void Write( unsigned int reg, unsigned int data);
+    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 );
+    *  Sets test mode which causes all display LEDs to emit light with full brightess.
+    *  @param mode  true - test mode, false - normal operation.
+    */
+    void TestMode(bool mode);
+    
+    /**
+    *  Sets amount of digits to be used by this display.
+    *  @param digits_no  1 - one digit, (2-7), 8 - all 8 digits.
+    */
+    void UseDigitsNo(unsigned int digits_no);
 
     /**
-    *  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){ 
-        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){ 
-        WriteFloat(value); 
-        return *this; 
-        };
+    *  Selects for which digits Code-B data decoding is used.
+    *  @param mode  0x00 - no decoding, 0x0F - digits 0-3, 0xFF - all digits.
+    */
+    void DecodeMode(unsigned int mode);
 
     /**
-    *  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);
+    *  Sends data to selected digit.
+    *  @param digit_no  Selected digit (0-7).
+    *  @param digit_no  Data to display.
+    */
+    void WriteDigit(unsigned int digit_no, unsigned int value);
 
     /**
-    *  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   
+    *  Sets display brightness.
+    *  @param intensity  0x00 - minimum brightness, 0x0F - maximum brightness.
+    */
+    void Intensity(unsigned int intensity);
+
+    /**
+    *  Sets display operation mode.
+    *  @param mode  true - normal operation, false - shutdown mode.
+    */
+    void OperationMode(bool mode);
+    
+    /**
+    *  Initial setup of this display.
+    *  8-digit blank decimal display set to nimimal brightness.
+    *  Supports display chain on single SPI (m_position > 0).
     */   
-    static void SetupAll (void);
-   
-private:
-   /// Pointer for the class instance to a particular SPI bus
-   SPI *max7221_spi;
-   /// pointer for the class instance of a particular load signal
-   DigitalOut *max7221_cs;
-   ///  id of the class instance
-   int id;
-   /// pointer to the number of devices connected to the SPI bus instance this device instance is connected to.
-   int *maxInUse;
-   
-   ///For the class we have a static set of values.  There are 2 SPI buses, 2 load signals, and 2 counters of the number of devices connected to a SPI bus.
-   static SPI *spi;
-//   static SPI *spi2;
-   static DigitalOut *cs;
-//   static DigitalOut *load2;
-   static int maxInUseSPI;
-//   static int maxInUseSPI2;
+    void Setup(void);
 };
 
 #endif
\ No newline at end of file