Igor Skochinsky / Mbed 2 deprecated FastIO

Fast GPIO using C++ templates. Now with port I/O.

Dependencies:   mbed

FastIO.h@4:b8e40f2a0aac, 2010-05-25 (annotated)

Committer:
igorsk
Date:
Tue May 25 08:35:39 2010 +0000
Revision:
4:b8e40f2a0aac
Parent:
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#ifndef __FAST_IO_H





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#define __FAST_IO_H





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#include "mbed.h"





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// Super-fast DigitalOut-like class for mbed





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//   by Igor Skochinsky





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// includes FastOut, FastPortOut and MaskedPortOut classes





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// usage:





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//   FastOut<LED2> led2;





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//   FastPortOut<Port0, LED_MASK> ledport2;





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//   MaskedPortOut<Port0, LED_MASK> ledport3;





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//   led2 = 1;





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//   ledport2 = LED_MASK;





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//   ledport3 = LED_MASK;





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// MaskedPortOut works the same way as FastPortOut, but it pre-sets the pin mask so that write can be done in one operation





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// this makes things faster but you can't control other pins of the port, even with other classes





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// pin definitions in PinNames.h start from LPC_GPIO0_BASE for P0_0 and there are 32 pins to a port (0 to 31)





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// Thus:





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// pin = LPC_GPIO0_BASE + port * 32 + bit





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// port = (pin - LPC_GPIO0_BASE) / 32





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// bit  = (pin - LPC_GPIO0_BASE) % 32





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#define PORTNO(pin) (((pin) - P0_0)/32)





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#define BITNO(pin)  (((pin) - P0_0)%32)





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// calculate the GPIO port definition for the pin





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// we rely on the fact that port structs are 0x20 bytes apart





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#define PORTDEF(pin) ((LPC_GPIO_TypeDef*)(LPC_GPIO0_BASE + PORTNO(pin)*0x20))





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#define PORTDEFPORT(port) ((LPC_GPIO_TypeDef*)(LPC_GPIO0_BASE + port*0x20))





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// calculate the mask for the pin's bit in the port





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#define PINMASK(pin) (1UL << BITNO(pin))





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// each port takes two PINSEL registers (8 bytes or 64 bits)





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// so there are 16 pins per PINSEL





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#define PINSELREG(pin)  (*(volatile uint32_t*)(LPC_PINCON_BASE + 4*(((pin) - P0_0)/16)))





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#define PINSELMASK(pin, v) (v << (((pin - P0_0)%16)*2) )





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// usage: FastOut<LED2> led2;





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// then use the same assignment operators as with DigitalOut





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template <PinName pin> class FastOut





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{





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public:





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    FastOut()





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    {





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        // set PINSEL bits to 0b00 (GPIO)





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        PINSELREG(pin) &= ~PINSELMASK(pin, 3);





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        // set FIODIR bit to 1 (output)





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        PORTDEF(pin)->FIODIR |= PINMASK(pin);





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    }





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    void write(int value)





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    { 





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        if ( value )





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            PORTDEF(pin)->FIOSET = PINMASK(pin);





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        else





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            PORTDEF(pin)->FIOCLR = PINMASK(pin);





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    } 





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    int read()





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    {





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        return PORTDEF(pin)->FIOPIN & PINMASK(pin) != 0;





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    }





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    FastOut& operator= (int value) { write(value); return *this; };





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    FastOut& operator= (FastOut& rhs) { return write(rhs.read()); };





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    operator int() { return read(); };





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};





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#define PINSELREG(pin)  (*(volatile uint32_t*)(LPC_PINCON_BASE + 4*(((pin) - P0_0)/16)))





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#define PINSELMASK(pin, v) (v << (((pin - P0_0)%16)*2) )





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// usage: FastPortOut<Port0, mask> led2;





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// then use the same assignment operators as with DigitalOut





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template <enum PortName port, uint32_t mask = 0xFFFFFFFF> class FastPortOut





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{





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public:





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    FastPortOut()





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    {





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        // init pins selected by the mask





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        uint32_t pin = LPC_GPIO0_BASE + port * 32;





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        for ( uint32_t pinmask = mask; pinmask !=0; pinmask >>= 1 )





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        {





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            if ( pinmask & 1 )





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            {





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                // set PINSEL bits to 0b00 (GPIO)





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                PINSELREG(pin) &= ~PINSELMASK(pin, 3);





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                // set FIODIR bit to 1 (output)





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                PORTDEF(pin)->FIODIR |= PINMASK(pin);





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            }





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            pin++;





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        }





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    }





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    void write(int value)





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    {





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        PORTDEFPORT(port)->FIOSET = value & mask;





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        PORTDEFPORT(port)->FIOCLR = ~value & mask;





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    } 





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    int read()





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    {





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        return PORTDEFPORT(port)->FIOPIN & mask;





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    }





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    FastPortOut& operator= (int value) { write(value); return *this; };





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    FastPortOut& operator= (FastPortOut& rhs) { return write(rhs.read()); };





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    operator int() { return read(); };





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};





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// usage: MaskedPortOut<Port0, mask> led2;





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// then use the same assignment operators as with DigitalOut





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template <enum PortName port, uint32_t mask = 0xFFFFFFFF> class MaskedPortOut





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{





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public:





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    MaskedPortOut()





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    {





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        // init pins selected by the mask





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        uint32_t pin = LPC_GPIO0_BASE + port * 32;





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        for ( uint32_t pinmask = mask; pinmask !=0; pinmask >>= 1 )





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        {





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            if ( pinmask & 1 )





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            {





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                // set PINSEL bits to 0b00 (GPIO)





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                PINSELREG(pin) &= ~PINSELMASK(pin, 3);





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                // set FIODIR bit to 1 (output)





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                PORTDEF(pin)->FIODIR |= PINMASK(pin);





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            }





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            pin++;





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        }





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        // set mask





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        PORTDEFPORT(port)->FIOMASK = mask;





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    }





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    void write(int value)





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    {





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        PORTDEFPORT(port)->FIOPIN = value;





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    } 





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    int read()





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    {





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        return PORTDEFPORT(port)->FIOPIN;





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    }





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    MaskedPortOut& operator= (int value) { write(value); return *this; };





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    MaskedPortOut& operator= (MaskedPortOut& rhs) { return write(rhs.read()); };





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    operator int() { return read(); };





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};





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#endif