基于FPGA的嵌入式系统开发流程
Nios处理器分立元件：
RAM的设置：M9K;Data Width:12KByte;Total Size:12Kbyte
PIO的设置：Reset Value:0x00;
CPU的设置：Instruction Cache:2Kbytes
Interval Timer的设置：Presets(预先装置):Full-featured(全功能)
NiosII例化代码:
module first_q2_prj(clk,ext_rst_n,led_pio);
input clk;
input ext_rst_n;
output[7:0] led_pio;
wire rst_n;
sys_ctrl uut_sc(
.clk(clk),
.ext_rst_n(ext_rst_n),
.rst_n(rst_n)
);
first_nios_sys first_nios_sys_inst
(
.clk (clk),
.out_port_from_the_led_pio (led_pio),
.reset_n (rst_n)
);
endmodule
复位延迟代码：
module sys_ctrl(clk,ext_rst_n,rst_n); input clk; input ext_rst_n; output rst_n; reg[9:0] rst_cnt; reg rst_nr; always@(posedge clk or negedge ext_rst_n) if(!ext_rst_n) begin rst_cnt<=10'b0; rst_nr<=1'b0; end else if(rst_n!=10'd000) rst_cnt<=rst_cnt+1'b1; else rst_nr<=1'b1; assign rst_n=rst_nr; endmodule
NiosII Eclipse Reduce Library Size Setting:
NiosII软体部分代码：
/*************************************************************************
* Copyright (c) 2009 Altera Corporation, San Jose, California, USA. *
* All rights reserved. All use of this software and documentation is *
* subject to the License Agreement located at the end of this file below.*
*************************************************************************/
/******************************************************************************
*
* Description
* *************
* A simple program which, using an 8 bit variable, counts from 0 to ff,
* repeatedly. Output of this variable is displayed on the LEDs, the Seven
* Segment Display, and the LCD. The four "buttons" (SW0-SW3) are used
* to control output to these devices in the following manner:
* Button1 (SW0) => LED is "counting"
* Button2 (SW1) => Seven Segment is "counting"
* Button3 (SW2) => LCD is "counting"
* Button4 (SW3) => All of the peripherals are "counting".
*
* Upon completion of "counting", there is a short waiting period during
* which button/switch presses will be identified on STDOUT.
* NOTE: These buttons have not been de-bounced, so one button press may
* cause multiple notifications to STDOUT.
*
* Requirements
* **************
* This program requires the following devices to be configured:
* an LED PIO named 'led_pio',
* a Seven Segment Display PIO named 'seven_seg_pio',
* an LCD Display named 'lcd_display',
* a Button PIO named 'button_pio',
* a UART (JTAG or standard serial)
*
* Peripherals Exercised by SW
* *****************************
* LEDs
* Seven Segment Display
* LCD
* Buttons (SW0-SW3)
* UART (JTAG or serial)
* Software Files
* ****************
* count_binary.c ==> This file.
* main() is contained here, as is the lion's share of the
* functionality.
* count_binary.h ==> Contains some very simple VT100 ESC sequence defines
* for formatting text to the LCD Display.
*
*
* Useful Functions
* *****************
* count_binary.c (this file) has the following useful functions.
* static void sevenseg_set_hex( int hex )
* - Defines a hexadecimal display map for the seven segment display.
* static void handle_button_interrupts( void* context, alt_u32 id)
* static void init_button_pio()
* - These are useful functions because they demonstrate how to write
* and register an interrupt handler with the system library.
*
* count_binary.h
* The file defines some useful VT100 escape sequences for use on the LCD
* Display.
*/
#include "count_binary.h"
/* A "loop counter" variable. */
static alt_u8 count;
/* A variable to hold the value of the button pio edge capture register. */
volatile int edge_capture;
/* Button pio functions */
/*
Some simple functions to:
1. Define an interrupt handler function.
2. Register this handler in the system.
*/
/*******************************************************************
* static void handle_button_interrupts( void* context, alt_u32 id)*
* *
* Handle interrupts from the buttons. *
* This interrupt event is triggered by a button/switch press. *
* This handler sets *context to the value read from the button *
* edge capture register. The button edge capture register *
* is then cleared and normal program execution resumes. *
* The value stored in *context is used to control program flow *
* in the rest of this program's routines. *
* *
* Provision is made here for systems that might have either the *
* legacy or enhanced interrupt API active, or for the Nios II IDE *
* which does not support enhanced interrupts. For systems created *
* using the Nios II softawre build tools, the enhanced API is *
* recommended for new designs. *
******************************************************************/
#ifdef BUTTON_PIO_BASE
#ifdef ALT_ENHANCED_INTERRUPT_API_PRESENT
static void handle_button_interrupts(void* context)
#else
static void handle_button_interrupts(void* context, alt_u32 id)
#endif
{
/* Cast context to edge_capture's type. It is important that this be
* declared volatile to avoid unwanted compiler optimization.
*/
volatile int* edge_capture_ptr = (volatile int*) context;
/* Store the value in the Button's edge capture register in *context. */
*edge_capture_ptr = IORD_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE);
/* Reset the Button's edge capture register. */
IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE, 0);
/*
* Read the PIO to delay ISR exit. This is done to prevent a spurious
* interrupt in systems with high processor -> pio latency and fast
* interrupts.
*/
IORD_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE);
}
/* Initialize the button_pio. */
static void init_button_pio()
{
/* Recast the edge_capture pointer to match the alt_irq_register() function
* prototype. */
void* edge_capture_ptr = (void*) &edge_capture;
/* Enable all 4 button interrupts. */
IOWR_ALTERA_AVALON_PIO_IRQ_MASK(BUTTON_PIO_BASE, 0xf);
/* Reset the edge capture register. */
IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE, 0x0);
/* Register the interrupt handler. */
#ifdef ALT_ENHANCED_INTERRUPT_API_PRESENT
alt_ic_isr_register(BUTTON_PIO_IRQ_INTERRUPT_CONTROLLER_ID, BUTTON_PIO_IRQ,
handle_button_interrupts, edge_capture_ptr, 0x0);
#else
alt_irq_register( BUTTON_PIO_IRQ, edge_capture_ptr,
handle_button_interrupts);
#endif
}
#endif /* BUTTON_PIO_BASE */
/* Seven Segment Display PIO Functions
* sevenseg_set_hex() -- implements a hex digit map.
*/
#ifdef SEVEN_SEG_PIO_BASE
static void sevenseg_set_hex(int hex)
{
static alt_u8 segments[16] = {
0x81, 0xCF, 0x92, 0x86, 0xCC, 0xA4, 0xA0, 0x8F, 0x80, 0x84, /* 0-9 */
0x88, 0xE0, 0xF2, 0xC2, 0xB0, 0xB8 }; /* a-f */
unsigned int data = segments[hex & 15] | (segments[(hex >> 4) & 15] << 8);
IOWR_ALTERA_AVALON_PIO_DATA(SEVEN_SEG_PIO_BASE, data);
}
#endif
/* Functions used in main loop
* lcd_init() -- Writes a simple message to the top line of the LCD.
* initial_message() -- Writes a message to stdout (usually JTAG_UART).
* count_<device>() -- Implements the counting on the respective device.
* handle_button_press() -- Determines what to do when one of the buttons
* is pressed.
*/
static void lcd_init( FILE *lcd )
{
/* If the LCD Display exists, write a simple message on the first line. */
LCD_PRINTF(lcd, "%c%s Counting will be displayed below...", ESC,
ESC_TOP_LEFT);
}
static void initial_message()
{
printf("\n\n**************************\n");
printf("* Hello from Nios II! *\n");
printf("* Counting from 00 to ff *\n");
printf("**************************\n");
}
/********************************************************
* The following functions write the value of the global*
* variable 'count' to 3 peripherals, if they exist in *
* the system. Specifically: *
* The LEDs will illuminate, the Seven Segment Display *
* will count from 00-ff, and the LCD will display the *
* hex value as the program loops. *
* *****************************************************/
/* static void count_led()
*
* Illuminate LEDs with the value of 'count', if they
* exist in the system
*/
static void count_led()
{
#ifdef LED_PIO_BASE
IOWR_ALTERA_AVALON_PIO_DATA(
LED_PIO_BASE,
count
);
#endif
}
/* static void count_sevenseg()
*
* Display value of 'count' on the Seven Segment Display
*/
static void count_sevenseg()
{
#ifdef SEVEN_SEG_PIO_BASE
sevenseg_set_hex(count);
#endif
}
/* static void count_lcd()
*
* Display the value of 'count' on the LCD Display, if it
* exists in the system.
*
* NOTE: A HAL character device driver is used, so the LCD
* is treated as an I/O device (i.e.: using fprintf). You
* can read more about HAL drivers <link/reference here>.
*/
static void count_lcd( void* arg )
{
FILE *lcd = (FILE*) arg;
LCD_PRINTF(lcd, "%c%s 0x%x\n", ESC, ESC_COL2_INDENT5, count);
}
/* count_all merely combines all three peripherals counting */
static void count_all( void* arg )
{
count_led();
count_sevenseg();
count_lcd( arg );
printf("%02x, ", count);
}
static void handle_button_press(alt_u8 type, FILE *lcd)
{
/* Button press actions while counting. */
if (type == 'c')
{
switch (edge_capture)
{
/* Button 1: Output counting to LED only. */
case 0x1:
count_led();
break;
/* Button 2: Output counting to SEVEN SEG only. */
case 0x2:
count_sevenseg();
break;
/* Button 3: Output counting to D only. */
case 0x4:
count_lcd( lcd );
break;
/* Button 4: Output counting to LED, SEVEN_SEG, and D. */
case 0x8:
count_all( lcd );
break;
/* If value ends up being something different (shouldn't) do
same as 8. */
default:
count_all( lcd );
break;
}
}
/* If 'type' is anything else, assume we're "waiting"...*/
else
{
switch (edge_capture)
{
case 0x1:
printf( "Button 1\n");
edge_capture = 0;
break;
case 0x2:
printf( "Button 2\n");
edge_capture = 0;
break;
case 0x4:
printf( "Button 3\n");
edge_capture = 0;
break;
case 0x8:
printf( "Button 4\n");
edge_capture = 0;
break;
default:
printf( "Button press UNKNOWN!!\n");
}
}
}
/*******************************************************************************
* int main() *
* *
* Implements a continuous loop counting from 00 to FF. 'count' is the loop *
* counter. *
* The value of 'count' will be displayed on one or more of the following 3 *
* devices, based upon hardware availability: LEDs, Seven Segment Display, *
* and the LCD Display. *
* *
* During the counting loop, a switch press of SW0-SW3 will affect the *
* behavior of the counting in the following way: *
* *
* SW0 - Only the LED will be "counting". *
* SW1 - Only the Seven Segment Display will be "counting". *
* SW2 - Only the LCD Display will be "counting". *
* SW3 - All devices "counting". *
* *
* There is also a 7 second "wait", following the count loop, *
* during which button presses are still *
* detected. *
* *
* The result of the button press is displayed on STDOUT. *
* *
* NOTE: These buttons are not de-bounced, so you may get multiple *
* messages for what you thought was a single button press! *
* *
* NOTE: References to Buttons 1-4 correspond to SW0-SW3 on the Development *
* Board. *
******************************************************************************/
int main(void)
{
int i;
int wait_time;
FILE * lcd;
count = 0;
/* Initialize the LCD, if there is one.
*/
lcd = LCD_OPEN();
if(lcd != NULL) {lcd_init( lcd );}
/* Initialize the button pio. */
#ifdef BUTTON_PIO_BASE
init_button_pio();
#endif
/* Initial message to output. */
initial_message();
/* Continue 0-ff counting loop. */
while( 1 )
{
usleep(100000);
if (edge_capture != 0)
{
/* Handle button presses while counting... */
handle_button_press('c', lcd);
}
/* If no button presses, try to output counting to all. */
else
{
count_all( lcd );
}
/*
* If done counting, wait about 7 seconds...
* detect button presses while waiting.
*/
if( count == 0xff )
{
LCD_PRINTF(lcd, "%c%s %c%s %c%s Waiting...\n", ESC, ESC_TOP_LEFT,
ESC, ESC_CLEAR, ESC, ESC_COL1_INDENT5);
printf("\nWaiting...");
edge_capture = 0; /* Reset to 0 during wait/pause period. */
/* Clear the 2nd. line of the LCD screen. */
LCD_PRINTF(lcd, "%c%s, %c%s", ESC, ESC_COL2_INDENT5, ESC,
ESC_CLEAR);
wait_time = 0;
for (i = 0; i<70; ++i)
{
printf(".");
wait_time = i/10;
LCD_PRINTF(lcd, "%c%s %ds\n", ESC, ESC_COL2_INDENT5,
wait_time+1);
if (edge_capture != 0)
{
printf( "\nYou pushed: " );
handle_button_press('w', lcd);
}
usleep(100000); /* Sleep for 0.1s. */
}
/* Output the "loop start" messages before looping, again.
*/
initial_message();
lcd_init( lcd );
}
count++;
}
LCD_CLOSE(lcd);
return 0;
}
/******************************************************************************
* *
* License Agreement *
* *
* Copyright (c) 2006 Altera Corporation, San Jose, California, USA. *
* All rights reserved. *
* *
* Permission is hereby granted, free of charge, to any person obtaining a *
* copy of this software and associated documentation files (the "Software"), *
* to deal in the Software without restriction, including without limitation *
* the rights to use, copy, modify, merge, publish, distribute, sublicense, *
* and/or sell copies of the Software, and to permit persons to whom the *
* Software is furnished to do so, subject to the following conditions: *
* *
* The above copyright notice and this permission notice shall be included in *
* all copies or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR *
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE *
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER *
* DEALINGS IN THE SOFTWARE. *
* *
* This agreement shall be governed in all respects by the laws of the State *
* of California and by the laws of the United States of America. *
* Altera does not recommend, suggest or require that this reference design *
* file be used in conjunction or combination with any other product. *
******************************************************************************/