Frank Vannieuwkerke
Sample code on how to pass an optional function pointer to a library and set a single pin to either InterruptIn or DigitalOut.
This code can be used as a template to create a library where a single pin can be set to either InterruptIn or DigitalOut.
There are 3 ways to instantiate the library (example using the KL25Z board):
// 2 parameters : Only SDA and SCL are declared. DemoClass sensor(PTE0, PTE1); // 3 parameters : SDA, SCL and a DigitalOut are declared. DemoClass sensor(PTE0, PTE1, PTD7); // SDA, SCL // 4 parameters : SDA, SCL, InterruptIn and a user function pointer are declared. DemoClass sensor(PTE0, PTE1, PTD7, &sensor_irq); // ISR mode
Notice that the 3rd pin declaration switches from DigitalOut to InterruptIn when the user function pointer is added.
Revision 0:0a6e921b085b, committed 2014-05-03
- Comitter:
- frankvnk
- Date:
- Sat May 03 16:15:38 2014 +0000
- Commit message:
- Initial release
Changed in this revision
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DemoClass/DemoClass.cpp Sat May 03 16:15:38 2014 +0000
@@ -0,0 +1,34 @@
+#include "DemoClass.h"
+
+InterruptIn *_irqpin;
+DigitalOut *_syncpin;
+
+// Depending on how the ctor is called, irqsync is either set to none, InterruptIn or DigitalOut
+DemoClass::DemoClass(PinName sda, PinName scl, PinName irqsync, void (*fptr)(void)) : _i2c(sda, scl)
+{
+ // When both irqsync and fptr are nonzero, we use InterruptIn: irqsync pin is interrupt input and Attach ISR.
+ if((irqsync != NC) && (fptr != NULL))
+ {
+ _irqpin = new InterruptIn(irqsync); // Create InterruptIn pin
+ _irqpin->fall(this, &DemoClass::_sensorISR); // Attach falling interrupt to local ISR
+ _fptr.attach(fptr); // Attach function pointer to user function
+ }
+
+ // When fptr is not defined, we use DigitalOut: irqsync pin is digital output.
+ if((irqsync != NC) && (fptr == NULL))
+ {
+ _syncpin = new DigitalOut(irqsync); // Create DigitalOut pin
+ _syncpin->write(0); // Set pin to 0
+ }
+}
+
+bool DemoClass::Status(void)
+{
+ return (1);
+}
+
+void DemoClass::_sensorISR(void)
+{
+ uint8_t statret = Status(); // Read a status register (eg : to clear an interrupt flag).
+ _fptr.call(); // Call the user-ISR
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DemoClass/DemoClass.h Sat May 03 16:15:38 2014 +0000
@@ -0,0 +1,33 @@
+#ifndef DemoClass_H
+#define DemoClass_H
+
+#include "mbed.h"
+
+class DemoClass {
+public:
+ /**
+ * \brief Create an object connected to I2C bus, irq input or digital output and user-ISR.
+ * \param sda SDA pin.
+ * \param scl SCL pin.
+ * \param irqsync Interrupt input when called with user-ISR pointer.
+ * Digital output when called without user-ISR pointer.
+ * \param fptr Pointer to user-ISR.
+ * \return none
+ */
+
+ DemoClass(PinName sda, PinName scl, PinName irqsync = NC, void (*fptr)(void) = NULL);
+
+ /**
+ * \brief Example status function.
+ * \param none.
+ * \return Always 1.
+ */
+ bool Status(void);
+
+private:
+ I2C _i2c;
+ FunctionPointer _fptr;
+ void _sensorISR(void);
+};
+
+#endif
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sat May 03 16:15:38 2014 +0000
@@ -0,0 +1,23 @@
+#include "mbed.h"
+#include "DemoClass.h"
+
+bool Overflow = 0;
+
+// Forward declaration of the user-ISR
+void sensor_irq(void);
+
+// 3 possible constructor calls (current example uses KL25Z pins)
+//DemoClass sensor(PTE0, PTE1); // Free running mode
+//DemoClass sensor(PTE0, PTE1, PTD7); // Sync mode
+DemoClass sensor(PTE0, PTE1, PTD7, &sensor_irq); // ISR mode
+
+void sensor_irq(void)
+{
+ Overflow = 1;
+}
+
+int main()
+{
+ while(1)
+ if(Overflow) Overflow = 0;
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Sat May 03 16:15:38 2014 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/8e73be2a2ac1 \ No newline at end of file