Revision 5:b93b28e126fe, committed 2021-10-20

Comitter:

okano

Date:

Wed Oct 20 08:17:05 2021 +0000

Parent:

4:507e37f8008d

Commit message:

comment added

Changed in this revision

--- a/main.cpp	Fri Aug 01 07:11:31 2014 +0000
+++ b/main.cpp	Wed Oct 20 08:17:05 2021 +0000
@@ -3,7 +3,7 @@
 
 I2C i2c( p28, p27 );    //  SDA, SCL
 
-#define     SLAVE_ADDR              0x02
+#define     SLAVE_ADDR              0x02    //  I2C target (slave) adress
 
 void register_write( char addr, char data );
 
@@ -11,23 +11,25 @@
 {
     //  initialization
 
-    register_write( MODE1,      0x00 );
-    register_write( MODE2,      0x25 );
-    register_write( LEDOUT0,    0xAA );
-    register_write( LEDOUT1,    0xAA );
-    register_write( LEDOUT2,    0xAA );
-    register_write( LEDOUT3,    0xAA );
-    register_write( IREFALL,    0x10 );
+    register_write( MODE1,      0x00 ); //  mode setting
+    register_write( MODE2,      0x25 ); //  mode setting
+    register_write( LEDOUT0,    0xAA ); //  PWM output setting for LED0  .. LED3 
+    register_write( LEDOUT1,    0xAA ); //  PWM output setting for LED4  .. LED7
+    register_write( LEDOUT2,    0xAA ); //  PWM output setting for LED8  .. LED11
+    register_write( LEDOUT3,    0xAA ); //  PWM output setting for LED12 .. LED15
+    register_write( IREFALL,    0x10 ); //  set all IREF register (output current setting)
 
     //  operation loop
 
     while ( 1 ) {
         
+        //  LED0 luminanceset from 0 to max by PWM
         for ( int i = 0; i < 256; i++ ) {
             register_write( PWM0, i );
             wait( 0.01 );
         }
 
+        //  LED0 luminanceset from max to 0 by PWM
         for ( int i = 255; i >= 0; i-- ) {
             register_write( PWM0, i );
             wait( 0.01 );
@@ -35,12 +37,12 @@
     }
 }
 
-void register_write( char addr, char data )
+void register_write( char addr /* register address */, char data /* data value */ )
 {
     char    d[ 2 ];
 
     d[ 0 ]   = addr;
     d[ 1 ]   = data;
-    i2c.write( SLAVE_ADDR, d, 2 );
+    i2c.write( SLAVE_ADDR, d, 2 );  //  two bytes transfer to I2C target device which has address of SLAVE_ADDR
 }