Revision 9:43c7f34925ac, committed 2015-12-12

Comitter:

dzoni

Date:

Sat Dec 12 20:14:52 2015 +0000

Parent:

8:308d188a2d3a

Commit message:

1. Optimization: change from wait(float) to wait_us(int)

Changed in this revision

diff -r 308d188a2d3a -r 43c7f34925ac TextLCD.cpp
--- a/TextLCD.cpp	Thu Jan 02 21:07:01 2014 +0000
+++ b/TextLCD.cpp	Sat Dec 12 20:14:52 2015 +0000
@@ -23,6 +23,10 @@
 #include "TextLCD.h"
 #include "mbed.h"
 
+#define TIME_WAIT_POWER_UP_US   (150000) // Time to ensure reliable power-up (150 ms)
+#define TIME_WAIT_1_64_MS_US    (1640)   // Time 1.64 ms for duration of a command
+#define TIME_WAIT_40_US         (40)     // Time 40 us for duration of a command
+
 TextLCD::TextLCD(PinName rs, PinName e, PinName d4, PinName d5,
                  PinName d6, PinName d7, LCDType type) : _rs(rs),
         _e(e), _d(d4, d5, d6, d7),
@@ -31,15 +35,15 @@
     _e  = 1;
     _rs = 0;            // command mode
 
-    wait(0.015);        // Wait 15ms to ensure powered up
+    wait_us(TIME_WAIT_POWER_UP_US);        // Wait to ensure powered up
 
     // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
     for (int i=0; i<3; i++) {
         writeByte(0x3);
-        wait(0.00164);  // this command takes 1.64ms, so wait for it
+        wait_us(TIME_WAIT_1_64_MS_US);  // this command takes 1.64ms, so wait for it
     }
-    writeByte(0x2);     // 4-bit mode
-    wait(0.000040f);    // most instructions take 40us
+    writeByte(0x2);             // 4-bit mode
+    wait_us(TIME_WAIT_40_US);   // most instructions take 40us
 
     writeCommand(0x28); // Function set 001 BW N F - -
     writeCommand(0x0C);
@@ -55,7 +59,7 @@
 
 void TextLCD::cls() {
     writeCommand(0x01); // cls, and set cursor to 0
-    wait(0.00164f);     // This command takes 1.64 ms
+    wait_us(TIME_WAIT_1_64_MS_US);     // This command takes 1.64 ms
     locate(0, 0);
 }
 
@@ -91,14 +95,14 @@
 
 void TextLCD::writeByte(int value) {
     _d = value >> 4;
-    wait(0.000040f); // most instructions take 40us
+    wait_us(TIME_WAIT_40_US); // most instructions take 40us
     _e = 0;
-    wait(0.000040f);
+    wait_us(TIME_WAIT_40_US); // most instructions take 40us
     _e = 1;
     _d = value >> 0;
-    wait(0.000040f);
+    wait_us(TIME_WAIT_40_US); // most instructions take 40us
     _e = 0;
-    wait(0.000040f);  // most instructions take 40us
+    wait_us(TIME_WAIT_40_US); // most instructions take 40us
     _e = 1;
 }