nios II--实验6——串口软件部分

/*

* "Hello World" example.

*

* This example prints ‘Hello from Nios II‘ to the STDOUT stream. It runs on

* the Nios II ‘standard‘, ‘full_featured‘, ‘fast‘, and ‘low_cost‘ example

* designs. It runs with or without the MicroC/OS-II RTOS and requires a STDOUT

* device in your system‘s hardware.

* The memory footprint of this hosted application is ~69 kbytes by default

* using the standard reference design.

*

* For a reduced footprint version of this template, and an explanation of how

* to reduce the memory footprint for a given application, see the

* "small_hello_world" template.

*

*/

#include <stdio.h>

#include <unistd.h>

#include <io.h>

#include <string.h>

#include "system.h"

#include "alt_types.h"

#include "altera_avalon_uart_regs.h"

#include "sys\alt_irq.h"

?

static alt_u8 txdata = 0;

static alt_u8 rxdata = 0;

//UART中断服务函数

static void uart_isr(void * context,alt_u32 id)

{

rxdata = IORD_ALTERA_AVALON_UART_RXDATA(UART_BASE);

txdata = rxdata;

//查询发送准备好信号，如果没有准备好，则等待

while(!((IORD_ALTERA_AVALON_UART_STATUS(UART_BASE)&ALTERA_AVALON_UART_STATUS_TRDY_MSK)));

//发送准备好，发送txdata

IOWR_ALTERA_AVALON_UART_TXDATA(UART_BASE,txdata);

}

void uart_init()

{

//清除状态寄存器

IOWR_ALTERA_AVALON_UART_STATUS(UART_BASE,0);

//使能接受准备好中断

IOWR_ALTERA_AVALON_UART_CONTROL(UART_BASE,0X80);

}

int main()

{

printf("Please Start!\n");

//注册UART中断服务函数

alt_ic_isr_register(UART_IRQ_INTERRUPT_CONTROLLER_ID,

UART_IRQ,uart_isr,NULL,0x00);

uart_init();

while(1){}

return 0;

}