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.
Diff: DemoClass/DemoClass.cpp
- Revision:
- 0:0a6e921b085b
--- /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 +}