孟宪元第7章代码

// SOPC Builder基于Verilog语言的自定制指令模板
module <user_instr>
(
clk, // CPU＇s master-input clk <required for multi-cycle>
reset, // CPU＇s master asynchronous reset <required for multi-cycle>
clk_en, // Clock-qualifier <required for multi-cycle>
start, // True when this instr. issues <required for multi-cycle>
done, // True when instr. completes <required for variable muli-cycle>
dataa, // operand A <always required>
datab, // operand B <optional>
n, // N-field selector <required for extended>
a, // operand A selector <used for Internal register file access>
b, // operand b selector <used for Internal register file access>
c, // result destination selector <used for Internal register file access>
readra, // register file index <used for Internal register file access>
readrb, // register file index <used for Internal register file access>
writerc,// register file index <used for Internal register file access>
result // result <always required>
);
input clk;
input reset;
input clk_en;
input start;
input readra;
input readrb;
input writerc;
input [7:0] n;
input [4:0] a;
input [4:0] b;
input [4:0] c;
input [31:0]dataa;
input [31:0]datab;
output[31:0]result;
output done;
// Port Declaration
// Wire Declaration
// Integer Declaration
// Concurrent Assignment
// Always Construct
endmodule
//例7-1
/*用Nios II的fprintf标准函数对DE2开发板上的字符模式设备LCD进行编程，让LCD分两行显示“One World ”（后有7个空白符）和“One Dream ”（空白符前4后3）。

*/
# include <unistd.h>
# include <stdio.h>
# include <string.h>
# include <io.h>
# include “system.h”
void main( )
{ FILE *lcd;
Lcd=fopen(“/dev/lcd_16207_0”,”w”);
fprintf(lcd,”One World \n“);
fprintf(lcd,”One Dream \n“);
fclose(lcd);
}
//例7-2
//使用Altera提供的专用函数alt_avalon_spi_command( )操作SPI外设发送和接收数据# include “system.h”
# include “altera_avalon_spi_regs.h”
# include “altera_avalon_spi.h”
# include “alt_types.h”
int main( )
{
alt_u8 Txbuf(16);
alt_u8 Rxbuf(16);
int i;
int cnt = 16;
for (i=0; i<16; i++)
{
Txbuf[i] = (alt_u8)i+1);
}
while(1)
{
alt_avalon_spi_command (SPI_BASE, 0,16,Txbuf,0,Rxbuf,0);
//使用了专用函数alt_avalon_spi_command，参数说明：
// SPI_BASE——SPI核的基地址，
// 0——标志位，0表示选通连接其上的SPI从器件
// 16——欲写入的数据长度
// Txbuf——欲写入的数据缓冲区
// 0——欲读出的数据长度
// Rxbuf——欲读出的数据缓冲区
// 0——标志位，0表示在每次访问后释放SS_n信号
while(cnt--);
cnt = 32;
};
return 0;
};
//例7-3
/*使用宏操作读取DE2开发板上18只电平开关SW上的数据，并用七段数码管显示读出的数据。

*/
# include “alt_types.h”
# include <stdio.h>
# include <unistd.h>
# include “system.h”
# include “sys/alt_irq.h”
# include “alt_avalon_pio_regs.h”
# include “alt_types.h”
int alt_main(void)
{
int key;
key = IORD(SWITCH_PIO_BASE,0); // 使用了宏操作IORD（）
IOWR(SEG7_DISPLAY_BASE,0,key); // 使用了宏操作IOWR（）
}
// 基于模板生成待调整的hello_led.c程序
#include"system.h"
#include"altera_avalon_pio_regs.h"
#include"alt_types.h"
int main (void) __attribute__ ((weak, alias ("alt_main")));
int alt_main (void)
{
alt_u8 led = 0x2;
alt_u8 dir = 0;
volatile int i;
while (1)
{
if (led & 0x81)
{
dir = (dir ^ 0x1);
}
if (dir)
{
led = led >> 1;
}
else
{
led = led << 1;
}
IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, led);
//因System.h仅有PIO_BASE的宏定义，需将LED_PIO_BASE改为PIO_BASE
i = 0;
while (i<200000) //需将“200000”改大，以便观察到LED的移位闪烁
i++;
}
return 0;
}
（第7章代码完）。