: Category: OS; Published: 31 July 2017; Hits: 51351

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Nios® II is an softcore 32-bit processor developed by Altera to be implemented over all Altera (INTEL) FPGA and SoC families.

Some NIOS-II-e Gen2 features:

No license required.
Use fewer than 700 logic elements.
6-stage pipeline runnning up to 30 DMIPS at 175 MHz in Nios II /e "economy" processor (Dhrystones 2.1 benchmark).
Deterministic and jitter free real-time performance.
Vector Interrupt Controller.
Custom instructions (ability to use FPGA hardware to accelerate a function).
Supported by industry-leading real-time operating systems (RTOS).
Nios II fast processor core can use a memory management unit (MMU) to run embedded Linux* operating system.

One way to optimize hardware resources use of Nios-II processor is implementing an real Time Operating System (RTOS) and NIOS-II is a excellent processor to run RTOS. Nios-II processor is supported by a lot of RTOS and one of the most popular and robust is the FreeRTOS.

Some FreeRTOS features:

Free for use in commercial applications.
Scalable, simple and easy to use.
Simple - the core of the RTOS kernel is contained in only 3 .C files.
Scheduler can be configured for both preemptive or cooperative operation
Free tutorial books and training to educate engineers

In this article, we present all steps to implement the last FreeRTOS (v9.0) versión over the NIOS-II processor. All step presented area developed in Quartus II 17.0 version and tested in DE0-nano development board.

Create Project using "DE0 Nano System Builder"

Open project using Quartus 17

From Quartus: File, Open Project..

Open project using Quartus 17

Create NIOS-II instantiation using Qsys tool

From Quartus: Tools, Qsys..
Save as niosII.qsys
From IP catalog, include this components and configure.

IP component	Name of component in project	Detailed Configuration
clock_source	clock_50
altera_nios2_gen2	cpu
altera_avalon_sysid_qsys	sys_id
altera_avalon_new_sdram_controller	sdram
altera_avalon_epcs_flash_controller	epcs
altpll	sys_pll
clock_source	sys_clk
altera_avalon_timer	sys_clk_timer
clock_source	ram_clk
altera_avalon_jtag_uart	jtag
altera_up_avalon_parallel_port	LED_Pio
altera_up_avalon_parallel_port	Button_Pio
altera_up_avalon_parallel_port	Switch_Pio
altera_avalon_uart	uart
altera_up_avalon_parallel_port	IO_Pio

Interconnect all components included in project in the next way.

Generate HDL of NIOS-II instantiation.

From Qsys: Generate, Generate HDL...

Connect NIOS-II HDL with FPGA hardware pins.

write follow code in Quartus project, verilog file.

 niosII u0 (
.clk_clk (CLOCK_50), // clk.clk
.epcs_dclk (EPCS_DCLK), // epcs.dclk
.epcs_sce (EPCS_NCSO), // .sce
.epcs_sdo (EPCS_ASDO), // .sdo
.epcs_data0 (EPCS_DATA0), // .data0
.port_led_export (LED), // port_led.export
.port_key_export (KEY), // port_key.export
.port_sw_export (SW), // port_sw.export
.port_gpio_0_export (GPIO_0[31:0]), // port_gpio_0.export
.ram_clk_clk (DRAM_CLK), // ram_clk.clk
.reset_reset_n (1'b1), // reset.reset_n 
.uart_rxd (GPIO_0[32]), // uart.rxd
.uart_txd (GPIO_0[33]), // .txd
.sdram_addr (DRAM_ADDR), // sdram.addr
.sdram_ba (DRAM_BA), // .ba
.sdram_cas_n (DRAM_CAS_N), // .cas_n
.sdram_cke (DRAM_CKE), // .cke
.sdram_cs_n (DRAM_CS_N), // .cs_n
.sdram_dq (DRAM_DQ), // .dq
.sdram_dqm (DRAM_DQM), // .dqm
.sdram_ras_n (DRAM_RAS_N), // .ras_n
.sdram_we_n (DRAM_WE_N) // .we_n
);

Include NIOS-II HDL to Quartus Project

From Quartus: Project, Add/Remove files in Project..
Add niosII.qsys file to project.

Compile Quartus project

From Quartus: Processing, Start Compilation.

Programming FPGA DE0-nano.

From Quartus: Tools, Programmer
click over Start Button

Create C/C++ project from Eclipse IDE

From Quartus: Tools, Nios II Sofware Build Tool for Eclipse.
Select a workspace
From Eclipse: File, New, Nios II Application and BSP from Template

Create NIOS II application from template
- Nios II SOPC: Search for niosII. sopcinfo in to project folder
- Project Name: Whatever you want
- Project Template: Hello World
- Finish

Import FreeRTOS to Eclipse Project

Download FreeRTOS port for Nios-II
Drag and drop FreeRTOS folder to Eclipse Nios Project.

Include FreeRTOS folders to compile path in properties of Eclipse Nios Project.

Edit hello_wolrd.c to create task and run FreeRTOS.

In this example, in hello_wolrd.c are created two task. This is the "hello_world.c" code. Copy and paste in your own eclipse project.

/*
 *
 * [File Name]     hello_world.c
 * [Platform]      DE0-nano
 * [Project]       NiosII & FreeRTOS
 * [Version]       1.00
 * [Author]        ea.rincon11 - ErnestoARC
 * [Date]          24/07/2017
 * [Language]      'C'
 * [History]       1.20 - Edited from original file included in FreeRTOS V9.0.0 Nios Example
 */
//-----------------------------------------------------------------------
// Standard C/C++ Includes
//-----------------------------------------------------------------------
#include <stddef.h>
#include <stdio.h>
#include <string.h>
//-----------------------------------------------------------------------
// Scheduler Includes
//-----------------------------------------------------------------------
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "partest.h"
//-----------------------------------------------------------------------
// Constants
//-----------------------------------------------------------------------
/* The rate at which the Print out message controlled by the 'Task1' */
#define mainTASK1_PERIOD	( 500 )
/* The rate at which the Print out message controlled by the 'Task2' */
#define mainTASK2_PERIOD	( 1000 )
 
/* Priority definitions for the tasks in the demo application. */
#define mainTASK1_PRIORITY		( tskIDLE_PRIORITY + 1 )
/* Priority definitions for the tasks in the demo application. */
#define mainTASK2_PRIORITY		( tskIDLE_PRIORITY + 2 )
//-----------------------------------------------------------------------
// Function Prototypes
//-----------------------------------------------------------------------
static void prvPrintTask1( void *pvParameters );
static void prvPrintTask2( void *pvParameters );
//-----------------------------------------------------------------------
// Main Function
//-----------------------------------------------------------------------
int main()
{
	/* Configure any hardware required for this demo. */
	vParTestInitialise();
 
	printf("Hello from Nios II!\n");
 
	/* prvPrintTask1 uses sprintf so requires more stack. */
	xTaskCreate( prvPrintTask1, "Task1", configMINIMAL_STACK_SIZE, NULL, mainTASK1_PRIORITY, NULL );
	/* prvPrintTask2 uses sprintf so requires more stack. */
	xTaskCreate( prvPrintTask2, "Task2", configMINIMAL_STACK_SIZE, NULL, mainTASK2_PRIORITY, NULL );
 
      /* Finally start the scheduler. */
	vTaskStartScheduler();
 
	/* Will only reach here if there is insufficient heap available to start
	the scheduler. */
	for( ;; );
 
  return 0;
}
/*-----------------------------------------------------------*/
static void prvPrintTask1( void *pvParameters )
{
	for( ;; )
	{
		/* Wait until it is time to run the tests again. */
		vTaskDelay( mainTASK1_PERIOD / portTICK_PERIOD_MS);
 
        /* Print out an message */
        printf( "NIOS II Task1\r\n" );
        /*Control LED 1 DE0-NANO*/
        vParTestToggleLED(1);
	}
}
/*-----------------------------------------------------------*/
static void prvPrintTask2( void *pvParameters )
{
	for( ;; )
	{
		/* Wait until it is time to run the tests again. */
		vTaskDelay( mainTASK2_PERIOD / portTICK_PERIOD_MS);
 
        /* Print out an message */
        printf( "NIOS II Task2\r\n" );
 
        /*Control LED 2 DE0-NANO*/
        vParTestToggleLED(2);
	}
}
/*-----------------------------------------------------------*/
////////////////////////////////////////////////////////////////////////////////
// EOF
////////////////////////////////////////////////////////////////////////////////