NXP Freescale Kinetis KEA128 Study Notes 3--GPIO Module (I)

{

//Hope for input

BCLR(bit, GPIO_PDDR_REG(gpio_ptr));

}

}

//===========================================================================

//Function name: gpio_set

//Function returns: None

//Parameter description: port_pin: port number | pin number (e.g.: PORTB|(5) means pin 5 of port B)

// state: initial state of the pin (0 = low level, 1 = high level)

//Function summary: Set the pin state to low or high

//===========================================================================

void gpio_set(uint_16 port_pin, uint_8 state)

{

//Local variable declaration

GPIO_MemMapPtr gpio_ptr; //Declare port_ptr as a GPIO structure type pointer

gpio_ptr_bit(port_pin,&gpio_ptr,&bit); //Calculate the base address and the offset of the pin in the register

//Determine whether the pin is output 1 or 0 based on the parameter state

if (1==state) 

{

BSET(bit,gpio_ptr->PDOR); //The corresponding position is 1

} else {

BCLR(bit,gpio_ptr->PDOR);//The corresponding position is 0

}

}

//===========================================================================

//Function name: gpio_get

//Function returns: the state of the specified pin (1 or 0)

//Parameter description: port_pin: port number | pin number (e.g.: PORTB|(5) means pin 5 of port B)

//Function summary: Get the status of the specified pin (1 or 0)

//===========================================================================

uint_8 gpio_get(uint_16 port_pin)

{

//Local variable declaration

GPIO_MemMapPtr gpio_ptr; //Declare port_ptr as a GPIO structure type pointer

gpio_ptr_bit(port_pin,&gpio_ptr,&bit); //Calculate the base address and the offset of the pin in the register

// Return the status of the pin

return ((BGET(bit,gpio_ptr->PDIR))>=1 ? 1:0);

}

//===========================================================================

//Function name: gpio_reverse

//Function returns: None

//Parameter description: port_pin: port number | pin number (e.g.: PORTB|(5) means pin 5 of port B)

//Function summary: Invert the output state of the specified pin.

//===========================================================================

void gpio_reverse(uint_16 port_pin)

{

//Local variable declaration

GPIO_MemMapPtr gpio_ptr; //Declare port_ptr as a GPIO structure type pointer

gpio_ptr_bit(port_pin,&gpio_ptr,&bit); //Calculate the base address and the offset of the pin in the register

//Reverse the output state of the specified pin

BSET(bit,gpio_ptr->PTOR);

}

//===========================================================================

//Function name: gpio_pull

//Function returns: None

//Parameter description: port_pin: port number | pin number (e.g.: PORTB|(5) means pin 5 of port B)

// pullselect: pin pull-up enable selection (0 = pull-up disabled, 1 = pull-up enabled)

//Function summary: Pull the specified pin high

//===========================================================================

void gpio_pull(uint_16 port_pin, uint_8 pullselect)

{

//Local variable declaration

uint_8 port; //port number

uint_8 pin; //pin number

gpio_port_pin_num(port_pin, &port, &pin); //parse out the port number and pin number

//Calculate the offset of the pin in the register

if (port < 4) //Port number is PORTA~PORTD

{

//The number of pins

bit = 8 * port + pin;

if (1==pullselect){BSET(bit,PORT_PUE0);}//Port pull-up enable low register 0 pull-up enable

else {BCLR(bit,PORT_PUE0);}//Pull-up disable (disabled)

}

else if(3 {

//The number of pins

bit = 8 * (port - 4) + pin;

if (1==pullselect){BSET(bit,PORT_PUE1);}//Port pull-up enable low register 1 pull-up enable

else {BCLR(bit,PORT_PUE1);}

}

else //Port number is PORTI

{

//The number of pins

bit = 8 * (port - 8) + pin;

if (1==pullselect){BSET(bit,PORT_PUE2);}//Port pull-up enable low register 2 pull-up enable

else {BCLR(bit,PORT_PUE2);}

}

}

//----------------------The following is where the internal functions are stored----------------------------------------

//===========================================================================

//Function name: gpio_port_pin_num

//Function returns: None

//Parameter description: port_pin: port number | pin number (e.g.: PORTB|(5) means pin 5 of port B)

// port: the parsed port number

// pin: parsed pin number (0~8, the actual value is determined by the physical pin of the chip)

//Function summary: Parse the parameter port_pin (e.g. PORTB|(5)) to get the specific port number and pin number, and pass them out through port and pin.

// For example, PORTB|(5) is parsed as *port=PORTB, *pin=5).

//Note: port and pin are address parameters. The purpose is to bring back the result. No value is required before calling the function.

//===========================================================================

static void gpio_port_pin_num(uint_16 port_pin,uint_8* port,uint_8* pin)

{

*port = port_pin>>8;

*pin = port_pin;

}

//===========================================================================

//Function name: gpio_ptr_bit

//Function returns: None

//Parameter description: port_pin: port number | pin number (e.g.: PORTB|(5) means pin 5 of port B)

// gpio_ptr: parsed base address

//       bit: the offset of the pin in the register

//Function summary: Parse the passed parameter port_pin (e.g. PORTB|(5)), parse the base address and the offset of the pin in the register, and pass it out through gpio_ptr and bit.

// For example: PORTB|(5) is parsed as base address GPIOA_BASE_PTR, offset 13

//Note: port and pin are address parameters. The purpose is to bring back the result. No value is required before calling the function.

//===========================================================================

// Parse the base address and the pin's offset in the register

static void gpio_ptr_bit(uint_16 port_pin,GPIO_MemMapPtr* gpio_ptr,uint_32* bit)

{

uint_8 port; //port number

uint_8 pin; //pin number

gpio_port_pin_num(port_pin, &port, &pin); //parse out the port number and pin number

//Calculate the offset of the pin in the register

if (port < 4) //Port number is PORTA~PORTD

{

//The register base address where the port is located

*gpio_ptr = GPIOA_BASE_PTR;

//The number of pins

*bit = 8 * port + pin;

} 

else if(3 {

//The register base address where the port is located

*gpio_ptr = GPIOB_BASE_PTR;

//The number of pins

*bit = 8 * (port - 4) + pin;

}

else //Port number is PORTI

{

//The register base address where the port is located

*gpio_ptr = GPIOC_BASE_PTR;

//The number of pins

*bit = 8 * (port - 8) + pin;

}

}

//----------------------------End of internal function---------------------------------------