F28027程序

主要作用就是给函数一个初始值吧。应该程序运行时需要用到的函数都需要初始化。
至于不需要初始化的函数，你方便举个例程中的例子吗？可能得具体问题具体分析了

这是一个关于GPIO口的例程，但是他没有初始化 InitGpio(); ，我以前的理解是用到那个就初始化哪个，现在有点不太明白了，求指教


#include "DSP28x_Project.h" // Device Headerfile and Examples Include File

// Select the example to compile in. Only one example should be set as 1
// the rest should be set as 0.

#define EXAMPLE1 1 // Basic pinout configuration example
#define EXAMPLE2 0 // Communication pinout example

// Prototype statements for functions found within this file.
void Gpio_setup1(void);
void Gpio_setup2(void);

void main(void)
{
// WARNING: Always ensure you call memcpy before running any functions from RAM
// InitSysCtrl includes a call to a RAM based function and without a call to
// memcpy first, the processor will go "into the weeds"
#ifdef _FLASH
memcpy(&RamfuncsRunStart, &RamfuncsLoadStart, (size_t)&RamfuncsLoadSize);
#endif

// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the f2802x_SysCtrl.c file.
InitSysCtrl();

// Step 2. Initialize GPIO:
// This example function is found in the f2802x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio(); Skipped for this example

// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts
DINT;

// Initialize PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.
// This function is found in the f2802x_PieCtrl.c file.
InitPieCtrl();

// Disable CPU interrupts and clear all CPU interrupt flags:
IER = 0x0000;
IFR = 0x0000;

// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the interrupt
// is not used in this example. This is useful for debug purposes.
// The shell ISR routines are found in f2802x_DefaultIsr.c.
// This function is found in f2802x_PieVect.c.
InitPieVectTable();

// Step 4. Initialize all the Device Peripherals:
// Not required for this example

// Step 5. User specific code:

#if EXAMPLE1

// This example is a basic pinout
Gpio_setup1();

#endif // - EXAMPLE1

#if EXAMPLE2

// This example is a communications pinout
Gpio_setup2();

#endif

}

void Gpio_setup1(void)
{
// Example 1:
// Basic Pinout.
// This basic pinout includes:
// PWM1-3, TZ1-TZ4, SPI-A, EQEP1, SCI-A, I2C
// and a number of I/O pins

// These can be combined into single statements for improved
// code efficiency.

// Enable PWM1-3 on GPIO0-GPIO5
EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO0 = 0; // Enable pullup on GPIO0
GpioCtrlRegs.GPAPUD.bit.GPIO1 = 0; // Enable pullup on GPIO1
GpioCtrlRegs.GPAPUD.bit.GPIO2 = 0; // Enable pullup on GPIO2
GpioCtrlRegs.GPAPUD.bit.GPIO3 = 0; // Enable pullup on GPIO3
GpioCtrlRegs.GPAPUD.bit.GPIO4 = 0; // Enable pullup on GPIO4
GpioCtrlRegs.GPAPUD.bit.GPIO5 = 0; // Enable pullup on GPIO5
GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 1; // GPIO0 = PWM1A
GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 1; // GPIO1 = PWM1B
GpioCtrlRegs.GPAMUX1.bit.GPIO2 = 1; // GPIO2 = PWM2A
GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 1; // GPIO3 = PWM2B
GpioCtrlRegs.GPAMUX1.bit.GPIO4 = 1; // GPIO4 = PWM3A
GpioCtrlRegs.GPAMUX1.bit.GPIO5 = 1; // GPIO5 = PWM3B

// Enable an GPIO output on GPIO6&7, set it high
GpioCtrlRegs.GPAPUD.bit.GPIO6 = 0; // Enable pullup on GPIO6
GpioDataRegs.GPASET.bit.GPIO6 = 1; // Load output latch
GpioCtrlRegs.GPAMUX1.bit.GPIO6 = 0; // GPIO6 = GPIO6
GpioCtrlRegs.GPADIR.bit.GPIO6 = 1; // GPIO6 = output

GpioCtrlRegs.GPAPUD.bit.GPIO7 = 0; // Enable pullup on GPIO7
GpioDataRegs.GPASET.bit.GPIO7 = 1; // Load output latch
GpioCtrlRegs.GPAMUX1.bit.GPIO7 = 0; // GPIO7 = GPIO7
GpioCtrlRegs.GPADIR.bit.GPIO7 = 1; // GPIO7 = output

// Enable Trip Zone input on GPIO12
GpioCtrlRegs.GPAPUD.bit.GPIO12 = 0; // Enable pullup on GPIO12
GpioCtrlRegs.GPAQSEL1.bit.GPIO12 = 3; // asynch input
GpioCtrlRegs.GPAMUX1.bit.GPIO12 = 1; // GPIO12 = TZ1

// Enable SPI-A on GPIO16 - GPIO19
GpioCtrlRegs.GPAPUD.bit.GPIO16 = 0; // Enable pullup on GPIO16
GpioCtrlRegs.GPAPUD.bit.GPIO17 = 0; // Enable pullup on GPIO17
GpioCtrlRegs.GPAPUD.bit.GPIO18 = 0; // Enable pullup on GPIO18
GpioCtrlRegs.GPAPUD.bit.GPIO19 = 0; // Enable pullup on GPIO19
GpioCtrlRegs.GPAQSEL2.bit.GPIO16 = 3; // asynch input
GpioCtrlRegs.GPAQSEL2.bit.GPIO17 = 3; // asynch input
GpioCtrlRegs.GPAQSEL2.bit.GPIO18 = 3; // asynch input
GpioCtrlRegs.GPAQSEL2.bit.GPIO19 = 3; // asynch input
GpioCtrlRegs.GPAMUX2.bit.GPIO16 = 1; // GPIO16 = ***
GpioCtrlRegs.GPAMUX2.bit.GPIO17 = 1; // GPIO17 = SPIS0MIA
GpioCtrlRegs.GPAMUX2.bit.GPIO18 = 1; // GPIO18 = ***
GpioCtrlRegs.GPAMUX2.bit.GPIO19 = 1; // GPIO19 = SPISTEA

// Enable SCI-A on GPIO28 - GPIO29
GpioCtrlRegs.GPAPUD.bit.GPIO28 = 0; // Enable pullup on GPIO28
GpioCtrlRegs.GPAQSEL2.bit.GPIO28 = 3; // Asynch input
GpioCtrlRegs.GPAMUX2.bit.GPIO28 = 1; // GPIO28 = SCIRXDA
GpioCtrlRegs.GPAPUD.bit.GPIO29 = 0; // Enable pullup on GPIO29
GpioCtrlRegs.GPAMUX2.bit.GPIO29 = 1; // GPIO29 = SCITXDA

// Make GPIO34 an input
GpioCtrlRegs.GPBPUD.bit.GPIO34 = 0; // Enable pullup on GPIO34
GpioCtrlRegs.GPBMUX1.bit.GPIO34 = 0; // GPIO34 = GPIO34
GpioCtrlRegs.GPBDIR.bit.GPIO34 = 0; // GPIO34 = input
EDIS;
}

void Gpio_setup2(void)
{
// Example 1:
// Communications Pinout.
// This basic communications pinout includes:
// PWM1-3, SPI-A, SCI-A
// and a number of I/O pins

// Enable PWM1-3 on GPIO0-GPIO5
EALLOW;
GpioCtrlRegs.GPAPUD.bit.GPIO0 = 0; // Enable pullup on GPIO0
GpioCtrlRegs.GPAPUD.bit.GPIO1 = 0; // Enable pullup on GPIO1
GpioCtrlRegs.GPAPUD.bit.GPIO2 = 0; // Enable pullup on GPIO2
GpioCtrlRegs.GPAPUD.bit.GPIO3 = 0; // Enable pullup on GPIO3
GpioCtrlRegs.GPAPUD.bit.GPIO4 = 0; // Enable pullup on GPIO4
GpioCtrlRegs.GPAPUD.bit.GPIO5 = 0; // Enable pullup on GPIO5
GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 1; // GPIO0 = PWM1A
GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 1; // GPIO1 = PWM1B
GpioCtrlRegs.GPAMUX1.bit.GPIO2 = 1; // GPIO2 = PWM2A
GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 1; // GPIO3 = PWM2B
GpioCtrlRegs.GPAMUX1.bit.GPIO4 = 1; // GPIO4 = PWM3A
GpioCtrlRegs.GPAMUX1.bit.GPIO5 = 1; // GPIO5 = PWM3B

// Enable an GPIO output on GPIO6&7
GpioCtrlRegs.GPAPUD.bit.GPIO6 = 0; // Enable pullup on GPIO6
GpioDataRegs.GPASET.bit.GPIO6 = 1; // Load output latch
GpioCtrlRegs.GPAMUX1.bit.GPIO6 = 0; // GPIO6 = GPIO6
GpioCtrlRegs.GPADIR.bit.GPIO6 = 1; // GPIO6 = output

GpioCtrlRegs.GPAPUD.bit.GPIO7 = 0; // Enable pullup on GPIO7
GpioDataRegs.GPASET.bit.GPIO7 = 1; // Load output latch
GpioCtrlRegs.GPAMUX1.bit.GPIO7 = 0; // GPIO7 = GPIO7
GpioCtrlRegs.GPADIR.bit.GPIO7 = 1; // GPIO7 = output

// Enable SPI-A on GPIO16 - GPIO19
GpioCtrlRegs.GPAPUD.bit.GPIO16 = 0; // Enable pullup on GPIO16 (***)
GpioCtrlRegs.GPAPUD.bit.GPIO17 = 0; // Enable pullup on GPIO17 (SPIS0MIA)
GpioCtrlRegs.GPAPUD.bit.GPIO18 = 0; // Enable pullup on GPIO18 (***)
GpioCtrlRegs.GPAPUD.bit.GPIO19 = 0; // Enable pullup on GPIO19 (SPISTEA)
GpioCtrlRegs.GPAQSEL2.bit.GPIO16 = 3; // asynch input
GpioCtrlRegs.GPAQSEL2.bit.GPIO17 = 3; // asynch input
GpioCtrlRegs.GPAQSEL2.bit.GPIO18 = 3; // asynch input
GpioCtrlRegs.GPAQSEL2.bit.GPIO19 = 3; // asynch input
GpioCtrlRegs.GPAMUX2.bit.GPIO16 = 1; // GPIO16 = ***
GpioCtrlRegs.GPAMUX2.bit.GPIO17 = 1; // GPIO17 = SPIS0MIA
GpioCtrlRegs.GPAMUX2.bit.GPIO18 = 1; // GPIO18 = ***
GpioCtrlRegs.GPAMUX2.bit.GPIO19 = 1; // GPIO19 = SPISTEA

// Enable SCI-A on GPIO28 - GPIO29
GpioCtrlRegs.GPAPUD.bit.GPIO28 = 0; // Enable pullup on GPIO28
GpioCtrlRegs.GPAQSEL2.bit.GPIO28 = 3; // asynch input
GpioCtrlRegs.GPAMUX2.bit.GPIO28 = 1; // GPIO28 = SCIRXDA
GpioCtrlRegs.GPAPUD.bit.GPIO29 = 0; // Enable pullup on GPIO29
GpioCtrlRegs.GPAMUX2.bit.GPIO29 = 1; // GPIO29 = SCITXDA

// Enable CAN-A on GPIO30 - GPIO31
GpioCtrlRegs.GPAPUD.bit.GPIO30 = 0; // Enable pullup on GPIO30
GpioCtrlRegs.GPAMUX2.bit.GPIO30 = 1; // GPIO30 = CANTXA
GpioCtrlRegs.GPAPUD.bit.GPIO31 = 0; // Enable pullup on GPIO31
GpioCtrlRegs.GPAQSEL2.bit.GPIO31 = 3; // asynch input
GpioCtrlRegs.GPAMUX2.bit.GPIO31 = 1; // GPIO31 = CANRXA

/* Applicable only on those packages with GPIO32 and GPIO33 pinned out
// Enable I2C-A on GPIO32 - GPIO33
GpioCtrlRegs.GPBPUD.bit.GPIO32 = 0; // Enable pullup on GPIO32
GpioCtrlRegs.GPBPUD.bit.GPIO33 = 0; // Enable pullup on GPIO33
GpioCtrlRegs.GPBQSEL1.bit.GPIO32 = 3; // asynch input
GpioCtrlRegs.GPBQSEL1.bit.GPIO32 = 3; // asynch input
GpioCtrlRegs.GPBMUX1.bit.GPIO32 = 1; // GPIO32 = SDAA
GpioCtrlRegs.GPBMUX1.bit.GPIO33 = 1; // GPIO33 = SCLA
*/
// Make GPIO34 an input
GpioCtrlRegs.GPBPUD.bit.GPIO34 = 0; // Enable pullup on GPIO34
GpioCtrlRegs.GPBMUX1.bit.GPIO34 = 0; // GPIO34 = GPIO34
GpioCtrlRegs.GPBDIR.bit.GPIO34 = 0; // GPIO34 = input

EDIS;
}

//===========================================================================
// No more.
//===========================================================================

一般来说，这里还要分为两点，初始化可以分为库函数中官方的初始化和我们自己写的初始化函数。
1.官方的初始化函数，一般是开启外设的时钟，给外设一个确切的状态。
2.一般来说，MCU复位的时候，都会有个默认状态的。自己写初始化函数的目的在于，再次给需要使用的外设一个确切的状态。