Revision 9:75bddbfbb692, committed 2015-11-24

Comitter:

ky3orr

Date:

Tue Nov 24 00:38:36 2015 +0000

Parent:

8:3f5901f2f813

Commit message:

All instances now share one SPI and /CS signal and operate in display chain.

Changed in this revision

diff -r 3f5901f2f813 -r 75bddbfbb692 Max7221.cpp
--- a/Max7221.cpp	Mon Nov 23 11:38:17 2015 +0000
+++ b/Max7221.cpp	Tue Nov 24 00:38:36 2015 +0000
@@ -10,13 +10,32 @@
 #include "mbed.h"
 #include "Max7221.h"
 
-Max7221::Max7221(SPI *spi, DigitalOut *cs, unsigned int position) :
-    mp_spi(spi),
-    mp_cs(cs),
-    m_position(position)
-{
+// Static members initialization
+SPI *Max7221::mp_spi = NULL;
+DigitalOut *Max7221::mp_cs = NULL;
+unsigned int Max7221::m_counter = 0;
+
+Max7221::Max7221() {
+    m_position = m_counter;
+    m_counter++;
 }
 
+Max7221::Max7221(SPI *spi, DigitalOut *cs) {
+    mp_spi = spi;
+    mp_cs = cs;
+    m_position = m_counter;
+    m_counter++;
+}
+
+void Max7221::SetSpi(SPI *spi) {
+    mp_spi = spi;
+}
+
+void Max7221::SetCs(DigitalOut *cs) {
+    mp_cs = cs;
+}
+    
+    
 void Max7221::CsLow()
 {
     if(mp_cs != NULL) {
@@ -42,11 +61,17 @@
     unsigned int i;
     
     CsLow();
+    if((m_counter > 1) && ((m_counter - 1) > m_position)) {
+        i = m_counter - 1 - m_position;
+        while(i--) {
+            WriteRaw(max7221_reg_noop, 0x00);
+        }        
+    }
     WriteRaw(reg, data);
     if(m_position > 0) {
         i = m_position;
         while(i--) {
-            WriteRaw(max7219_reg_noop, 0x00);
+            WriteRaw(max7221_reg_noop, 0x00);
         }
     }
     CsHigh();
@@ -54,40 +79,71 @@
 
 void Max7221::TestMode(bool mode) {
     if(mode) {
-        Write(max7219_reg_displayTest, 0x01);
+        Write(max7221_reg_displayTest, 0x01);
     } else {
-        Write(max7219_reg_displayTest, 0x00);
+        Write(max7221_reg_displayTest, 0x00);
     }
 }
 
 void Max7221::UseDigitsNo(unsigned int digits_no) {
     if((digits_no > 0) && (digits_no < 9)) {
-        Write(max7219_reg_scanLimit, (digits_no - 1));
+        Write(max7221_reg_scanLimit, (digits_no - 1));
     }
 }
 
 void Max7221::DecodeMode(unsigned int mode) {
-    Write(max7219_reg_decodeMode, mode);
+    Write(max7221_reg_decodeMode, mode);
 }
 
 void Max7221::WriteDigit(unsigned int digit_no, unsigned int value) {
+    unsigned int digit_reg;
+
     if(digit_no < 8) {
-        Write(digit_no, value);
-    }
+        switch(digit_no) {
+            case 0:
+                digit_reg = max7221_reg_digit0;
+                break;
+            case 1:
+                digit_reg = max7221_reg_digit1;
+                break;
+            case 2:
+                digit_reg = max7221_reg_digit2;
+                break;
+            case 3:
+                digit_reg = max7221_reg_digit3;
+                break;
+            case 4:
+                digit_reg = max7221_reg_digit4;
+                break;
+            case 5:
+                digit_reg = max7221_reg_digit5;
+                break;
+            case 6:
+                digit_reg = max7221_reg_digit6;
+                break;
+            case 7:
+                digit_reg = max7221_reg_digit7;
+                break;
+            default:
+                digit_reg = max7221_reg_noop;
+                break;
+        }
+        Write(digit_reg, value);
+    }    
 }
 
 void Max7221::Intensity(unsigned int intensity) {
     if(intensity > 0x0F) {
         intensity = 0x0F;
     }
-    Write(max7219_reg_intensity, intensity);
+    Write(max7221_reg_intensity, intensity);
 }
 
 void Max7221::OperationMode(bool mode) {
     if(mode) {
-        Write(max7219_reg_shutdown, 0x01);
+        Write(max7221_reg_shutdown, 0x01);
     } else {
-        Write(max7219_reg_shutdown, 0x00);
+        Write(max7221_reg_shutdown, 0x00);
     }
 }
 
@@ -97,7 +153,7 @@
     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
+    for(i=0;i<8;i++) {          // Clean all digits
         WriteDigit(i, 0x0F);
     }
     Intensity(0x01);            // Set lowest display intensity(0x00-0xFF)

diff -r 3f5901f2f813 -r 75bddbfbb692 Max7221.h
--- a/Max7221.h	Mon Nov 23 11:38:17 2015 +0000
+++ b/Max7221.h	Tue Nov 24 00:38:36 2015 +0000
@@ -11,12 +11,20 @@
 #define Max7221_H
 
 // MAX7219/7221 register map
-#define max7219_reg_noop         0x00
-#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 max7221_reg_noop         0x00
+#define max7221_reg_digit0       0x01
+#define max7221_reg_digit1       0x02
+#define max7221_reg_digit2       0x03
+#define max7221_reg_digit3       0x04
+#define max7221_reg_digit4       0x05
+#define max7221_reg_digit5       0x06
+#define max7221_reg_digit6       0x07
+#define max7221_reg_digit7       0x08
+#define max7221_reg_decodeMode   0x09
+#define max7221_reg_intensity    0x0A
+#define max7221_reg_scanLimit    0x0B
+#define max7221_reg_shutdown     0x0C
+#define max7221_reg_displayTest  0x0F
 
 // Logical values
 #define LOG_0 0
@@ -24,18 +32,35 @@
 
 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)
-
+    static SPI *mp_spi;             // SPI used for this display (no data transmission when NULL)
+    static DigitalOut *mp_cs;       // /CS signal (it should be handled manually when NULL)
+    static unsigned int m_counter;  // Total number of displays on SPI chain
+    unsigned int m_position;        // Display position on SPI chain (0 = 1'st)
 public:
     /**
     *  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 this signal is handled manually.
-    *  @param position  Position on SPI port (for displays connected in daisy-chain: DOUT-DIN). 0=1st.
+    *  At least one instance should set SPI and /CS pointers for display chain to work.
+    *  Use SetSpi() and SetCs() or parametrized constructor.
+    */
+    Max7221();
+
+    /**
+    *  Constructor.
+    *  Sets SPI and /CS pointers. Display chain is operational.
     */
-    Max7221(SPI *spi, DigitalOut *cs, unsigned int position=0);
+    Max7221(SPI *spi, DigitalOut *cs);
+
+    /**
+    *  Sets pointer to configured SPI.
+    *  SPI is used by all display instances.
+    */
+    void SetSpi(SPI *spi);
+
+    /**
+    *  Sets pointer to configured /CS signal.
+    *  /CS signal is used by all display instances.
+    */    
+    void SetCs(DigitalOut *cs);
 
     /**
     *  Method for setting /CS signal LOW (enable data reception).