//***************************************************************************** // // bitband.c - Bit-band manipulation example. // // Copyright (c) 2012-2017 Texas Instruments Incorporated. All rights reserved. // Software License Agreement // // Texas Instruments (TI) is supplying this software for use solely and // exclusively on TI's microcontroller products. The software is owned by // TI and/or its suppliers, and is protected under applicable copyright // laws. You may not combine this software with "viral" open-source // software in order to form a larger program. // // THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS. // NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT // NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY // CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL // DAMAGES, FOR ANY REASON WHATSOEVER. // // This is part of revision 2.1.4.178 of the EK-TM4C123GXL Firmware Package. // //***************************************************************************** #include <stdint.h> #include <stdbool.h> #include "inc/hw_memmap.h" #include "inc/hw_types.h" #include "inc/hw_gpio.h" #include "driverlib/debug.h" #include "driverlib/gpio.h" #include "driverlib/fpu.h" #include "driverlib/pin_map.h" #include "driverlib/sysctl.h" #include "driverlib/systick.h" #include "driverlib/rom.h" #include "driverlib/uart.h" #include "utils/uartstdio.h" //***************************************************************************** // //! \addtogroup example_list //! <h1>Bit-Banding (bitband)</h1> //! //! This example application demonstrates the use of the bit-banding //! capabilities of the Cortex-M4F microprocessor. All of SRAM and all of the //! peripherals reside within bit-band regions, meaning that bit-banding //! operations can be applied to any of them. In this example, a variable in //! SRAM is set to a particular value one bit at a time using bit-banding //! operations (it would be more efficient to do a single non-bit-banded write; //! this simply demonstrates the operation of bit-banding). // //***************************************************************************** //***************************************************************************** // // The value that is to be modified via bit-banding. // //***************************************************************************** static volatile uint32_t g_ui32Value; //***************************************************************************** // // The error routine that is called if the driver library encounters an error. // //***************************************************************************** #ifdef DEBUG void __error__(char *pcFilename, uint32_t ui32Line) {while(1){//// Hang on runtime error.//} } #endif //***************************************************************************** // // Configure the UART and its pins. This must be called before UARTprintf(). // //***************************************************************************** void ConfigureUART(void) {// Enable GPIOCROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);while(!(SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOD)));//// Enable UART1//ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART2);while(!(SysCtlPeripheralReady(SYSCTL_PERIPH_UART2)));//ulock PD7HWREG(GPIO_PORTD_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;HWREG(GPIO_PORTD_BASE + GPIO_O_CR) = 0xFF;//// Configure GPIO Pins for UART mode.//ROM_GPIOPinConfigure(GPIO_PD6_U2RX);ROM_GPIOPinConfigure(GPIO_PD7_U2TX);ROM_GPIOPinTypeUART(GPIO_PORTD_BASE, GPIO_PIN_6 | GPIO_PIN_7);//// Use the internal 16MHz oscillator as the UART clock source.//UARTClockSourceSet(UART2_BASE, UART_CLOCK_PIOSC);UARTConfigSetExpClk(UART2_BASE,16000000,115200,UART_CONFIG_PAR_NONE|UART_CONFIG_STOP_ONE|UART_CONFIG_WLEN_8);UARTEnable(UART2_BASE); } //***************************************************************************** // // This example demonstrates the use of bit-banding to set individual bits // within a word of SRAM. // //***************************************************************************** int main(void) {//// Set the clocking to run directly from the crystal.//ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |SYSCTL_XTAL_16MHZ);//// Initialize the UART interface.//ConfigureUART();//// Loop forever.//while(1){UARTCharPut(UART2_BASE,0xAA);} }
xyz549040622:
串口的配置和其他串口差不多,值得注意的是,UART2使用的PD6、PD7中PD7是特殊功能IO引脚,需要解锁才可以作为串口使用的。需要加上下面这句代码才可以的
HWREG(GPIO_PORTD_BASE + GPIO_O_LOCK) = GPIO_LOCK_KEY;HWREG(GPIO_PORTD_BASE + GPIO_O_CR) = 0xFF;头文件中需要包含#include "inc/hw_gpio.h"这个文件,因为
GPIO_O_LOCK、GPIO_O_CR、GPIO_LOCK_KEY的定义是在hw_gpio.h中实现的。
Loren Lai:
回复 xyz549040622:
感謝你, 可以使用了!
Seven Han:
回复 xyz549040622:
谢谢分享!