輸入限制:
輸入限制電路設計的十分靈活,你可以通過配置GPxQSELn寄存器來選擇輸入限制的類型。在GPIO的輸入模式中,可以配置爲與SYSCLKOUT同步或者採樣窗口限制。對於外設的輸入,還可以配置成異步模式。
不同步(異步輸入):此模式用於不要求同步或者本身就要異步的外設中,比如SCI,SPI和I2C。或者獨立於SYSCLKOUT的ePWM觸發。通用數字接口不能用此模式。
採樣窗口限制:在此模式中,輸入信號首先與SYSCLKOUT同步,然後用一定的週期來確定採樣信號。用3個或者6個,如果連續3個或者6個採樣週期都採樣到一樣的電平,這認爲是有效信號。採樣週期通過GPACTRL寄存器設置。
採樣週期:
能採樣到的最短信號電平寬度:
配置步驟(參考文檔SPRUFN3C):
1. 總體規劃IO口。
2. 使能或者除能上拉電阻(GPxPUD)。
ePWM模式默認除能,其他功能默認使能。模擬IO沒有上拉電阻。
3. 輸入採樣設置(GPxCTRL、 GPxQSELn)。
4. 選擇引腳功能(GPxMUXn or AIOMUXn)。
5. 如果是數字IO的話,選擇方向(GPxDIR or AIODIR)。
6. 選擇低功耗模式下的喚醒輸入引腳(GPIOLPMSEL)。
7. 選擇中斷源(GPIOxINTnSEL),極性(xINTnCR)。
程序設計:
實現板上的LED的驅動程序, LED相關IO的初始化都用同一個函數,分別提供了兩種種方法改變LED的狀態,一,通過一個函數實現。二、通過宏定義實現。第一種效率不高,佔用程序存儲空間較多,需要裝載參數和調用指令,子函數裏還有switch造成的跳轉表等,但是可以用過同一個函數設置LED的狀態,第二種效率高,通過三個調用設置三種狀態,只是一個複製語句,相當於三條彙編指令。建議使用第二種,通過條件編譯,保留第一種,但不編譯。最後,寫成兩個LED.c和LED.h文件,供日後使用。
程序:
/*********************************************
標題:LED_test.c
軟件平臺:CCS v5.2
硬件平臺:C2000 LaunchPad
主頻:60M
描述:練習gpio,測試led
基於2802x C/C++ Header Files V1.26
author:小船
data:2012-09-23
As supplied, this project is configured for "boot to SARAM"
operation. The 2802x Boot Mode table is shown below.
$Boot_Table
While an emulator is connected to your device, the TRSTn pin = 1,
which sets the device into EMU_BOOT boot mode. In this mode, the
peripheral boot modes are as follows:
Boot Mode: EMU_KEY EMU_BMODE
(0xD00) (0xD01)
---------------------------------------
Wait !=0x55AA X
I/O 0x55AA 0x0000
SCI 0x55AA 0x0001
Wait 0x55AA 0x0002
Get_Mode 0x55AA 0x0003
SPI 0x55AA 0x0004
I2C 0x55AA 0x0005
OTP 0x55AA 0x0006
Wait 0x55AA 0x0007
Wait 0x55AA 0x0008
SARAM 0x55AA 0x000A <-- "Boot to SARAM"
Flash 0x55AA 0x000B
Wait 0x55AA Other
Write EMU_KEY to 0xD00 and EMU_BMODE to 0xD01 via the debugger
according to the Boot Mode Table above. Build/Load project,
Reset the device, and Run example
$End_Boot_Table
**********************************************/
#include "DSP28x_Project.h" // Device Headerfile and Examples Include File
#define LED0 0x00000001
#define LED1 0x00000002
#define LED2 0x00000004
#define LED3 0x00000008
#define LED_on(LED_num) GpioDataRegs.GPACLEAR.all = LED_num
#define LED_off(LED_num) GpioDataRegs.GPASET.all = LED_num
#define LED_toggle(LED_num) GpioDataRegs.GPATOGGLE.all = LED_num
#define config_leds_by_funtion
#ifdef config_leds_by_funtion
enum LED_action {on, off, toggle};
void LEDs(Uint32 LED_num, enum LED_action action);
#endif
// Prototype statements for functions found within this file.
void Gpio_select(void);
void LEDs_init();
void main(void)
{
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP2802x_SysCtrl.c file.
InitSysCtrl();
// Step 2. Initalize GPIO:
// This example function is found in the DSP2802x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio(); // Skipped for this example
// For this example use the following configuration:
Gpio_select();
// 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 DSP2802x_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 DSP2802x_DefaultIsr.c.
// This function is found in DSP2802x_PieVect.c.
InitPieVectTable();
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP2802x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
// Step 5. User specific code:
LEDs_init();
while(1)
{
LEDs(LED0|LED1|LED2|LED3, off);
DELAY_US(1000000);
LEDs(LED1, on);
DELAY_US(1000000);
LEDs(LED2, toggle);
DELAY_US(1000000);
LED_toggle(LED1);
DELAY_US(1000000);
}
}
void LEDs_init()
{
EALLOW;
//使能上拉電阻
GpioCtrlRegs.GPAPUD.bit.GPIO0 = 1;
GpioCtrlRegs.GPAPUD.bit.GPIO1 = 1;
GpioCtrlRegs.GPAPUD.bit.GPIO2 = 1;
GpioCtrlRegs.GPAPUD.bit.GPIO3 = 1;
//選擇GPIO功能
GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0x0;
GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 0x0;
GpioCtrlRegs.GPAMUX1.bit.GPIO2 = 0x0;
GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 0x0;
//方向
GpioCtrlRegs.GPADIR.bit.GPIO0 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO1 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO2 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO3 = 1;
EDIS;
}
#ifdef config_leds_by_funtion
void LEDs(Uint32 LED_num, enum LED_action action)
{
switch (action)
{
case on:{
GpioDataRegs.GPACLEAR.all = LED_num;
break;
}
case off:{
GpioDataRegs.GPASET.all = LED_num;
break;
}
case toggle:{
GpioDataRegs.GPATOGGLE.all = LED_num;
break;
}
}
}
#endif
void Gpio_select(void)
{
EALLOW;
GpioCtrlRegs.GPAMUX1.all = 0x00000000; // All GPIO
GpioCtrlRegs.GPAMUX2.all = 0x00000000; // All GPIO
GpioCtrlRegs.GPBMUX1.all = 0x00000000; // All GPIO
GpioCtrlRegs.GPADIR.all = 0xFFFFFFFF; // All outputs
GpioCtrlRegs.GPBDIR.all = 0x0000000F; // All outputs
EDIS;
}
//===========================================================================
// No more.
//===========================================================================
/************************************
標題:LEDs.h
軟件平臺:CCS v5.2
硬件平臺:C2000 LaunchPad
主頻:60M
author:小船
data:2012-09-23
*************************************/
#ifndef LEDS_H_
#define LEDS_H_
#include "DSP28x_Project.h"
#define no_config_leds_by_funtion
#define LED0 0x00000001
#define LED1 0x00000002
#define LED2 0x00000004
#define LED3 0x00000008
#define LED_on(LED_num) GpioDataRegs.GPACLEAR.all = LED_num
#define LED_off(LED_num) GpioDataRegs.GPASET.all = LED_num
#define LED_toggle(LED_num) GpioDataRegs.GPATOGGLE.all = LED_num
#ifdef config_leds_by_funtion
enum LED_action {on, off, toggle};
void LEDs(Uint32 LED_num, enum LED_action action);
#endif
void LEDs_init();
#endif /* LEDS_H_ */
/************************************
標題:LEDs.c
軟件平臺:CCS v5.2
硬件平臺:C2000 LaunchPad
主頻:60M
author:小船
data:2012-09-23
*************************************/
#include "LEDs.h"
void LEDs_init()
{
EALLOW;
//使能上拉電阻
GpioCtrlRegs.GPAPUD.bit.GPIO0 = 1;
GpioCtrlRegs.GPAPUD.bit.GPIO1 = 1;
GpioCtrlRegs.GPAPUD.bit.GPIO2 = 1;
GpioCtrlRegs.GPAPUD.bit.GPIO3 = 1;
//選擇GPIO功能
GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0x0;
GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 0x0;
GpioCtrlRegs.GPAMUX1.bit.GPIO2 = 0x0;
GpioCtrlRegs.GPAMUX1.bit.GPIO3 = 0x0;
//方向
GpioCtrlRegs.GPADIR.bit.GPIO0 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO1 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO2 = 1;
GpioCtrlRegs.GPADIR.bit.GPIO3 = 1;
EDIS;
}
#ifdef config_leds_by_funtion
void LEDs(Uint32 LED_num, enum LED_action action)
{
switch (action)
{
case on:{
GpioDataRegs.GPACLEAR.all = LED_num;
break;
}
case off:{
GpioDataRegs.GPASET.all = LED_num;
break;
}
case toggle:{
GpioDataRegs.GPATOGGLE.all = LED_num;
break;
}
}
}
#endif