Ellie Griffiths
A simple counter using onboard LEDs, plus a screen and a button to display current state and switch between counting in Binary and Graycode. Thanks to Mr. Lerche for the GreyCode counter.
Revision 0:de4ce57020b0, committed 2011-06-29
- Comitter:
- Eggotape
- Date:
- Wed Jun 29 13:22:04 2011 +0000
- Commit message:
Changed in this revision
diff -r 000000000000 -r de4ce57020b0 DebouncedIn.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DebouncedIn.cpp Wed Jun 29 13:22:04 2011 +0000
@@ -0,0 +1,93 @@
+#include "DebouncedIn.h"
+#include "mbed.h"
+
+/*
+ * Constructor
+ */
+DebouncedIn::DebouncedIn(PinName in)
+ : _in(in) {
+
+ // reset all the flags and counters
+ _samples = 0;
+ _output = 0;
+ _output_last = 0;
+ _rising_flag = 0;
+ _falling_flag = 0;
+ _state_counter = 0;
+
+ // Attach ticker
+ _ticker.attach(this, &DebouncedIn::_sample, 0.005);
+}
+
+void DebouncedIn::_sample() {
+
+ // take a sample
+ _samples = _samples >> 1; // shift left
+
+ if (_in) {
+ _samples |= 0x80;
+ }
+
+ // examine the sample window, look for steady state
+ if (_samples == 0x00) {
+ _output = 0;
+ }
+ else if (_samples == 0xFF) {
+ _output = 1;
+ }
+
+
+ // Rising edge detection
+ if ((_output == 1) && (_output_last == 0)) {
+ _rising_flag++;
+ _state_counter = 0;
+ }
+
+ // Falling edge detection
+ else if ((_output == 0) && (_output_last == 1)) {
+ _falling_flag++;
+ _state_counter = 0;
+ }
+
+ // steady state
+ else {
+ _state_counter++;
+ }
+
+ // update the output
+ _output_last = _output;
+
+}
+
+
+
+// return number of rising edges
+int DebouncedIn::rising(void) {
+ int return_value = _rising_flag;
+ _rising_flag = 0;
+ return(return_value);
+}
+
+// return number of falling edges
+int DebouncedIn::falling(void) {
+ int return_value = _falling_flag;
+ _falling_flag = 0;
+ return(return_value);
+}
+
+// return number of ticsk we've bene steady for
+int DebouncedIn::steady(void) {
+return(_state_counter);
+}
+
+// return the debounced status
+int DebouncedIn::read(void) {
+ return(_output);
+}
+
+// shorthand for read()
+DebouncedIn::operator int() {
+ return read();
+}
+
+
diff -r 000000000000 -r de4ce57020b0 DebouncedIn.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DebouncedIn.h Wed Jun 29 13:22:04 2011 +0000
@@ -0,0 +1,31 @@
+#include "mbed.h"
+
+ class DebouncedIn {
+ public:
+ DebouncedIn(PinName in);
+
+ int read (void);
+ operator int();
+
+ int rising(void);
+ int falling(void);
+ int steady(void);
+
+ private :
+ // objects
+ DigitalIn _in;
+ Ticker _ticker;
+
+ // function to take a sample, and update flags
+ void _sample(void);
+
+ // counters and flags
+ int _samples;
+ int _output;
+ int _output_last;
+ int _rising_flag;
+ int _falling_flag;
+ int _state_counter;
+
+ };
+
\ No newline at end of file
diff -r 000000000000 -r de4ce57020b0 TextLCD.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TextLCD.lib Wed Jun 29 13:22:04 2011 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/simon/code/TextLCD/#e4cb7ddee0d3
diff -r 000000000000 -r de4ce57020b0 main.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Wed Jun 29 13:22:04 2011 +0000
@@ -0,0 +1,33 @@
+#include "mbed.h"
+#include "TextLCD.h"
+#include "DebouncedIn.h"
+
+BusOut led(LED4, LED3, LED2, LED1);
+unsigned char i;
+TextLCD lcd(p15, p16, p17, p18, p19, p20); // rs, e, d4-d7
+DebouncedIn setbutton(p5);
+
+int main() {
+ int state;
+ state = 0;
+ i = 0;
+ while(1) {
+ if (setbutton.rising()) {
+ state = !state;
+ }
+ if (state == 0) {
+ lcd.printf("Binary: %u\n", i);
+ led = i;
+ }
+ else if (state == 1) {
+ lcd.printf("Graycode: %u\n", i);
+ led = i^(i>>1);
+ }
+ wait(1);
+ i = i+1;
+ if (i == 16) {
+ i = 0;
+ }
+ lcd.cls();
+ }
+}
\ No newline at end of file
diff -r 000000000000 -r de4ce57020b0 mbed.bld --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Wed Jun 29 13:22:04 2011 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/63bcd7ba4912