Diff: main.cpp

Revision:

0:510bbea7c78e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Dec 11 08:50:58 2011 +0000
@@ -0,0 +1,101 @@
+#include "mbed.h"
+
+BusInOut colBus( p26, p25, p24);
+const PinName rowPins[] = { p30, p29, p28, p27 };
+
+volatile bool irqFinished = false;
+
+inline char toChar( unsigned char r, unsigned char c) {
+    static const char keytable[] = { '1', '2', '3', 'A',
+                                     '4', '5', '6', 'B',
+                                     '7', '8', '9', 'C',
+                                     '*', '0', '#', 'D'
+                                   };
+    return keytable[r*4+c];
+}
+
+inline char toBinary( unsigned char r, unsigned char c) {
+    static const char keytable[] = { 0x1, 0x2, 0x3, 0xC,
+                                     0x4, 0x5, 0x6, 0xD,
+                                     0x7, 0x8, 0x9, 0xE,
+                                     0xA, 0x0, 0xB, 0xF
+                                   };
+    return keytable[r*4+c];
+}
+
+inline void start() {
+    colBus.output();
+    colBus = 0xF;
+}
+
+// simple log2, only 4bits needed
+inline unsigned char _lg2( unsigned char c) {
+    return c&1 ? 0 : c&2 ? 1 : c&4 ? 2 : 3;
+}
+
+inline char pin2Row(PinName pin) {
+    return rowPins[0] == pin ? 0 : rowPins[1] == pin ? 1 : rowPins[2] == pin ? 2 : 3;
+}
+
+BusOut code(LED4, LED3, LED2, LED1); //show binary code of key
+
+void checkColumn(PinName pinPressed) {
+    {   //debounce
+        DigitalIn in(pinPressed);
+        for (char c=0; c<100; ++c) {
+            if ( !in.read()) {
+                irqFinished=true;
+                return;  // key not long enough pressed
+            }
+            wait_us(100);
+        }
+    }
+    // check column
+    DigitalOut p(pinPressed);
+    p = 0x1;
+    colBus.input();
+    unsigned char col = colBus.read();
+    if (col) {
+        col = _lg2(col);
+        {   // blink to show key pressed
+            code = 0;
+            wait_ms(150);
+            code = 0xF;
+            wait_ms(150);
+        }
+        char row = pin2Row(pinPressed);
+        code = toBinary(row,col);
+//        printf("%d, %d, %c\r\n", row, col, toChar(row,col));
+    }
+    irqFinished = true;
+}
+
+void trigger27() {
+    checkColumn(p27);
+}
+void trigger28() {
+    checkColumn(p28);
+}
+void trigger29() {
+    checkColumn(p29);
+}
+void trigger30() {
+    checkColumn(p30);
+}
+
+void checkRow() {
+    InterruptIn irqIn27(p27), irqIn28(p28), irqIn29(p29), irqIn30(p30);
+    irqIn27.rise( &trigger27);
+    irqIn28.rise( &trigger28);
+    irqIn29.rise( &trigger29);
+    irqIn30.rise( &trigger30);
+}
+
+int main() {
+    while (1) {
+        start();
+        irqFinished = false;
+        checkRow();
+        while (!irqFinished);
+    }
+}