A test program leveraging inputs and outputs on the DE-10 FPGA development board running a NIOS2 soft processor

nios2_test_pattern.c

//#ifdef NOTDEF
#include <sys/alt_stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include "altera_avalon_pio_regs.h"
#include "system.h"

#define LED_MASK 0b0000001111111111
#define HEX_MASK 0b01111111

// Make usage of inputs more readable
typedef union {
	struct {
		alt_u16 switch0 : 1; // Switch 0
		alt_u16 switch1 : 1; // Switch 1
		alt_u16 switch2 : 1; // Switch 2
		alt_u16 switch3 : 1; // Switch 3
		alt_u16 switch4 : 1; // Switch 4
		alt_u16 switch5 : 1; // Switch 5
		alt_u16 switch6 : 1; // Switch 6
		alt_u16 switch7 : 1; // Switch 7
		alt_u16 switch8 : 1; // Switch 8
		alt_u16 switch9 : 1; // Switch 9
		alt_u16 unused : 6;

		alt_u8 button0 : 1; // Button 0
		alt_u8 button1 : 1; // Button 1
		alt_u8 unused_2 : 6;

	} inputs;
	struct {
		alt_u16 pause : 1; // Master
		alt_u16 hex_edge : 1; // Pattern
		alt_u16 hex_long_edge : 1; // Modifier
        alt_u16 hex_random : 1; // Pattern

		alt_u16 variable_frequency : 1; // Master

        /// UNIMPLIMENTED FEATURES
        alt_u16 switch5 : 1;
		alt_u16 switch6 : 1;
		alt_u16 switch7 : 1;
		///

		alt_u16 led_explosion : 1; // Pattern
		alt_u16 led_flash : 1; // Pattern
		alt_u16 unused : 6;

		alt_u8 highlight : 1;
		alt_u8 frequency : 1;
		alt_u8 unused_2 : 6;

	} settings;
	struct {
		alt_u16 switches;
		alt_u8 buttons;
	} raw;
} settings_t;

typedef struct {
	alt_u16 led;
	alt_u8 hex[6];
} output_t;

typedef struct {
	alt_u8 hex_edge_index;
    alt_u8 variable_frequency_index;
    alt_u8 led_explosion_index;
	alt_u8 led_flash_on;
} state_t;

void set_settings(settings_t* settings, alt_u16 switch_datain, alt_u8 button_datain)
{
	settings->raw.switches = switch_datain;
	settings->raw.buttons = button_datain;
}

void write_output(output_t output)
{
	IOWR_ALTERA_AVALON_PIO_DATA(LED_BASE, output.led & LED_MASK);
	IOWR_ALTERA_AVALON_PIO_DATA(HEX0_BASE, ~output.hex[0] & HEX_MASK);
	IOWR_ALTERA_AVALON_PIO_DATA(HEX1_BASE, ~output.hex[1] & HEX_MASK);
	IOWR_ALTERA_AVALON_PIO_DATA(HEX2_BASE, ~output.hex[2] & HEX_MASK);
	IOWR_ALTERA_AVALON_PIO_DATA(HEX3_BASE, ~output.hex[3] & HEX_MASK);
	IOWR_ALTERA_AVALON_PIO_DATA(HEX4_BASE, ~output.hex[4] & HEX_MASK);
	IOWR_ALTERA_AVALON_PIO_DATA(HEX5_BASE, ~output.hex[5] & HEX_MASK);
}

alt_u16 variable_frequency_periods[] = {64,73,81,88,93,97,99,99,97,93,88,81,73,64,55,45,36,28,21,16,12,10,10,12,16,21,28,36,45,54}; // 10 - 100 - 10 sinusoidally
alt_u16 led_explosion_values[] = {
		0b0000000001111000,
		0b0000000001111100,
		0b0000000011111000,
		0b0000000000110000,
		0b0000000000010000,
		0b0000000000100000,
		0b0000000011001100,
		0b0000001010000101,
		0b0000001000000001,
		0b0000000100000010,
		0b0000000010000100,
		0b0000000000110000,
};

int main()
{
	settings_t settings = {0};
	output_t output = {0};
	state_t state = {0};
	long long ticks = 0;
	long long last_tap = 0;
	alt_u16 period = 100; //initial (ms)
	alt_u16 period_count = 0;

	// Main loop
	while (1)
	{
		// Delay
		alt_busy_sleep(1000); // 1ms should be slow enough to avoid debounce
		ticks++;

        // Obtain inputs (must be done in fast part of loop)
        alt_u16 switch_datain = IORD_ALTERA_AVALON_PIO_DATA(SWITCH_BASE) & 0b0000001111111111;
        alt_u8 button_datain = ~IORD_ALTERA_AVALON_PIO_DATA(BUTTON_BASE) & 0b0000000011;
        set_settings(&settings, switch_datain, button_datain);

		// Frequency set
        if (settings.settings.variable_frequency)
        {
            // Index is incremented in the slow clock
            period = variable_frequency_periods[state.variable_frequency_index];
        }
		else if (settings.settings.frequency)
		{
			// Button tapped
			long long delta = ticks - last_tap;
			if (last_tap != 0 && delta > 1 && delta < 3000) // 3 seconds seems reasonable max period
			{
				period = delta;
				printf("\nSetting period %d", period);
			}
            last_tap = ticks;
		}

        if (period_count <= period)
		{
            ++period_count;
            continue;
        }
		/// Above is run every clock 1ms, below every period ms

        period_count = 0;

		// Update state
		if (!settings.settings.pause)
		{
			memset(&output, 0, sizeof(output));

            // Variable frequency state
            state.variable_frequency_index = (state.variable_frequency_index + 1) % 30;

            // Highlight button
			if (settings.settings.highlight)
			{
				output.led = LED_MASK;
				for (int i = 0; i < 6; ++i)
					output.hex[i] = HEX_MASK;
			}

			// Hex edge pattern
			if (settings.settings.hex_edge)
			{
				// Increment state
				state.hex_edge_index = (state.hex_edge_index + 1) % 16; // There are 16 outer edge segments

				// Set output for this function
				for (alt_u8 i = 0; i < (settings.settings.hex_long_edge ? 6 : 2); ++i)
				{
					alt_u8 idx = (state.hex_edge_index + i) % 16;
					// 0-5 top; 6-11 bottom; 12-13 left; 14-15 right;
					// 0-5 top; 6-7 left; 8-13 bottom; 14-15 right;
					if (idx <= 5) output.hex[idx] |= 0b00000001;
					else if (idx <= 7) output.hex[5] |= 0b00010000 << (7 - idx);
					else if (idx <= 13) output.hex[13 - idx] |= 0b00001000;
					else output.hex[0] |= 0b00000010 << (15 - idx);
				}

			}

			// Random hex pattern
			if (settings.settings.hex_random)
			{
				alt_u8 idx = rand() % 6;
				output.hex[idx] = HEX_MASK;
			}

			// LED flash pattern
			if (settings.settings.led_flash)
			{
				if (!state.led_flash_on)
				{
					output.led |= LED_MASK;
				}
				state.led_flash_on = state.led_flash_on ^ 1;
			}

			if (settings.settings.led_explosion)
			{
				output.led |= led_explosion_values[state.led_explosion_index] & LED_MASK;
				state.led_explosion_index = (state.led_explosion_index + 1) % 12;
			}
		}

		// Write state to outputs
		write_output(output);
	}
}
//#endif