Y SI
Counts signal transitions on p30(CAP2.0) or p29(CAP2.1) for LPC1768 target. Can detecte rising, falling or both signal edge. Return the signal edge count during a period in seconds. In theory (Shannon's theorem) input signal frequency can up to 48 MHz with 96 MHz CCLK. But only tested with frequencys up to 20 MHz and it work.
Revision 5:b5e68cd91f09, committed 2020-12-02
- Comitter:
- YSI
- Date:
- Wed Dec 02 15:48:45 2020 +0000
- Parent:
- 4:b873a2fda102
- Commit message:
- add split start and stop count
Changed in this revision
| lib_ClockCounter.cpp | Show annotated file Show diff for this revision Revisions of this file |
| lib_ClockCounter.h | Show annotated file Show diff for this revision Revisions of this file |
diff -r b873a2fda102 -r b5e68cd91f09 lib_ClockCounter.cpp
--- a/lib_ClockCounter.cpp Tue Jan 07 15:00:14 2020 +0000
+++ b/lib_ClockCounter.cpp Wed Dec 02 15:48:45 2020 +0000
@@ -23,9 +23,12 @@
*/
#include "lib_ClockCounter.h"
+#include <cstdint>
ClockCounter::ClockCounter(PinName PIN_CAP2, edgeDetection EDGE)
{
+ _count = 0;
+ _selectPin = NC;
switch(PIN_CAP2)
{
case p30: case p29:
@@ -47,6 +50,45 @@
}
}
+void ClockCounter::setPin(PinName PIN_CAP2, edgeDetection EDGE)
+{
+ _selectPin = PIN_CAP2;
+ switch(PIN_CAP2)
+ {
+ case p30: case p29:
+ // PCONP => Power Mode Control register
+ LPC_SC->PCONP |= (0x1<<22); // Bit(22) 1 => Timer2 power on
+ // PCLKSEL1 => Peripheral Clock Selection register 1
+ LPC_SC->PCLKSEL1 |= (0x1<<12); // Bits(13,12) 01 => PCLK_TIMER2 = CCLK(96 MHz)
+ // TCR => Timer Control Register
+ LPC_TIM2->TCR = 0x0; // Bits(1,0) 00 => Timer2 disabled
+ // PINSEL0 => Pin Function Select register 0
+ LPC_PINCON->PINSEL0 |= (0x3<<((PIN_CAP2==p30)?8:10)); // Bits(9,8) 11 => pin function CAP2.0 (p30), Bits(11,10) 11 => pin function CAP2.1 (p29)
+ // CTCR => Count Control Register
+ LPC_TIM2->CTCR = ((PIN_CAP2==p30)?0:4)+EDGE; // Bits(3,2) 00 => CAP2.0 (p30 signal is counter clock) or 11 => CAP2.1 (p29 signal is counter clock), Bits(1,0) XX => timer is incremented on edge
+ // CCR => Capture Control Register
+ LPC_TIM2->CCR = 0x0; // Bits(5,4,3,2,1,0) 000000 => capture and interrupt on event disabled
+ break;
+ default:
+ break;
+ }
+}
+
+void ClockCounter::startCount(void)
+{
+ // TCR => Timer Control Register
+ LPC_TIM2->TCR = 0x2; // Bits(1,0) 10 => Timer2 count reset
+ LPC_TIM2->TCR = 0x1; // Bits(1,0) 01 => Timer2 enabled
+}
+
+int ClockCounter::stopCount(void)
+{
+ LPC_TIM2->TCR = 0x0; // Bits(1,0) 00 => Timer2 disabled
+ uint32_t TC = LPC_TIM2->TC; // TC => Timer Counter
+ _selectPin = NC;
+ return TC;
+}
+
int ClockCounter::getCount(int period)
{
// TCR => Timer Control Register
@@ -55,4 +97,9 @@
wait_us(period);
LPC_TIM2->TCR = 0x0; // Bits(1,0) 00 => Timer2 disabled
return LPC_TIM2->TC; // TC => Timer Counter
+}
+
+PinName ClockCounter::getPin(void)
+{
+ return _selectPin;
}
\ No newline at end of file
diff -r b873a2fda102 -r b5e68cd91f09 lib_ClockCounter.h
--- a/lib_ClockCounter.h Tue Jan 07 15:00:14 2020 +0000
+++ b/lib_ClockCounter.h Wed Dec 02 15:48:45 2020 +0000
@@ -51,11 +51,38 @@
*/
ClockCounter(PinName PIN_CAP2 = p30, edgeDetection EDGE = RISING);
+ /** Select an ClockCounter instance
+ *
+ * Configure LPC1768 TIMER2 with capture input PIN_CAP2 and detecte transition EDGE.
+ *
+ * @param PIN_CAP2 can be p30(CAP2.0) or p29(CAP2.1).
+ * @param EDGE can be RISING, FALLING, BOTH, default is RISING.
+ */
+ void setPin(PinName PIN_CAP2, edgeDetection EDGE = RISING);
+
+ /** Start the signal transition count
+ *
+ */
+ void startCount(void);
+
+ /** Stop and Get the signal transition count
+ *
+ */
+ int stopCount(void);
+
/** Get the signal transition count during period
*
* @param period default is 1000000 microsecond.
*/
int getCount(int period = 1000000);
+
+ /** Get the selected input PIN_CAP2 on started signal transition count
+ *
+ */
+ PinName getPin(void);
+private:
+ int _count;
+ PinName _selectPin;
};
#endif
#endif
\ No newline at end of file