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--- en:examples:digi:7seg [2009/03/25 06:32] – raivo.sell
+++ en:examples:digi:7seg [2010/02/04 12:28] (current) – removed mikk.leini
@@ Line 1: / Line 1: @@
-====== 7-segment numeric display ======
-{{:examples:7-seg.jpg|}}
-The Study board is equipped with 7-segment LED display and its driver A6275 ({{:examples:datasheets:a6275_led_driver.pdf|datasheet}}).
-The driver is connected to controller ports PORTC and PORTG.
-the schematics is shown below. The latch is connected to PORTG2, Serial to PORTC6 and clock to PORTC7.
-{{:examples:7seg_schematics.jpg?500}}
-===== Example 1 =====
-<code c>
-/*
-Basic ver 3 demo program
--seg function and demo
-Raivo Sell/Erki Leitaru
-*/
-#define F_CPU 14745600UL
-#include <avr/io.h>
-#include <util/delay.h>
-#define SET(x) |= (1<<x)  //defineeritakse kõrge bit pordis x
-#define CLR(x) &=~(1<<x)  //defineeritakse madal bit pordis x
-#define bit_get(p,m) ((p) & (m)) //returns 1 if bit is set, otherwise returns 0
-#define BIT(x) (0x01 << (x))
-void write_display (void);
-void nop_delay(int count);
-int i;//for cycle
-int digit;//digit to display on segment
-int nr;//segment map representation of the digit
-int delta;//to create a counting effect
-int num = 0;
-char buffer[7];
-void nop_delay(int count){
-	unsigned int j;
-	for (j=0; j<count;j++)	{asm volatile ("nop");}
-}
-void write_display (void) {
-	 switch (digit) //table read to get segment map representation of the digit
-	 {
-		 case 0 : nr = 0b00111111;break; //every bit corresponds to one segment
-		 case 1 : nr = 0b00000110;break; //"1"
-		 case 2 : nr = 0b01011011;break; //"2" and so on
-		 case 3 : nr = 0b01001111;break;
-		 case 4 : nr = 0b01100110;break;
-		 case 5 : nr = 0b01101101;break;
-		 case 6 : nr = 0b01111100;break;
-		 case 7 : nr = 0b00000111;break;
-		 case 8 : nr = 0b01111111;break;
-		 case 9 : nr = 0b01100111;break;
-		 default: nr = 0b01111001;//E
-	 }
-	 PORTG CLR (2); //latch low
-	 for(i=7; i>=0; i--) //for every bit in the byte
-	 {
-	 	//if bit is set, sets the data out pin
-		if (bit_get(nr, BIT(i))) PORTC SET (6); //serial out
-		else PORTC CLR (6); //serial out
-		PORTC SET (7); //clock high
-		nop_delay(8);//series of one cycle delays to ensure required timing (according to datasheet)
-		PORTC CLR (7); //clock low
-		nop_delay(8);
-	 }
-	 PORTG SET (2); //latch high
-}
-int main(void){
-	//7-seg init
-    PORTC = 0xFF; // set output high -> turn all LEDs off
-    DDRC  = 0xF8; // PC0...PC2 -> input; PC3...PC5 -> output for LED; PC7 & PC6 outputs for clock and data
-	DDRG  = 0x04;//PG2 is latch output
-	digit = 8;
-	delta = 1;//increment or decrement
-	while(1) {
-		num++;
-		_delay_ms(1000);
-		digit=digit+delta;//change digit by delta
-		if(digit>8) {delta=-1*delta;};//upper limit
-		if(digit<1) {delta=-1*delta;};//lower limit
-		write_display();
-	}
-}
-</code>
-===== Example 2 =====
-this example does not contain global variables and only functions are used. It is more easy to copy the functions into user program.
-All variables are 8 bit where possible.
-<code c>
-//
-// Simple up/down counting single 7-segment digit example.
-//
-// Raivo Sell, Erki Leitaru, Mikk Leini
-//
-// 2009
-//
-#define F_CPU 14745600UL
-// Include avrlibc
-#include <avr/io.h>
-#include <util/delay.h>
-// Macros for bit manipulation
-#define BIT(x) (1 << (x))
-#define SET(x) |=  BIT(x)
-#define CLR(x) &= ~BIT(x)
-#define SETTO(value, bit, to) value = ((to) ? value | BIT(bit) : value & ~BIT(bit))
-#define ISSET(value, bit) ((value) & (BIT(bit)))
-//
-// Delay cycle
-// On each cycle "no-operation" instruction is executed
-//
-void nop_delay(unsigned int count)
-{
-	for (unsigned int i = 0; i < count; i++)
-	{
-		asm volatile ("nop");
-	}
-}
-//
-// 7 segment display initialization
-//
-void segment_diplay_init(void)
-{
-	// Port C pin 7 - clock output, pin 6 data output
-	DDRC |= 0xC0;
-	// Port G pin 2 - latch output
-	DDRG |= 0x04;
-}
-//
-// Digit writing to 7 segment display
-//
-void segment_display_write(unsigned char digit)
-{
-	unsigned char map;
-	// Decimal to segment map
-	switch (digit)
-	{
-		case 0 : map = 0b00111111; break; // Every bit corresponds to one segment
-		case 1 : map = 0b00000110; break; // "1"
-		case 2 : map = 0b01011011; break; // "2"
-		case 3 : map = 0b01001111; break; // "3" and so on
-		case 4 : map = 0b01100110; break;
-		case 5 : map = 0b01101101; break;
-		case 6 : map = 0b01111100; break;
-		case 7 : map = 0b00000111; break;
-		case 8 : map = 0b01111111; break;
-		case 9 : map = 0b01100111; break;
-		default: map = 0b01111001;        // E like Error
-	}
-	// Latch low
-	PORTG CLR(2);
-	// Send every bit in the byte. MSB (most significant bit) first.
-	for (signed char i = 7; i >= 0; i--)
-	{
-		// If bit is set, sets the data out pin, otherwise not
-		SETTO(PORTC, 6, ISSET(map, i));
-		// Clock high for certain period
-		PORTC SET(7);
-		nop_delay(8);
-		// Clock low for certain period
-		PORTC CLR(7);
-		nop_delay(8);
-	}
-	// Latch high
-	PORTG SET(2);
-}
-//
-// Program entrance function
-//
-int main(void)
-{
-	unsigned char digit = 0; // Digit to display on segment
-	signed char delta = 1;   // Digit modifying value
-	// 7 segment display initialization
-	segment_diplay_init();
- 	// Endless loop
-	while (1)
-	{
-		// Write digit
-		segment_display_write(digit);
-		// Increase digit value by delta (which can be negative also)
-		digit += delta;
-		// Swap counting direction on 0 and 9
-		if (digit == 0) delta = +1;
-		if (digit == 9) delta = -1;
-		// Wait 1000 ms
-		_delay_ms(1000);
-	}
-}
-</code>
-===== Example 3 =====
-"pinops.h" library is used to simplify the port and pin usage.  [[en:examples:pinops|See here]] for more detail description.
-LED driver is replaced by the avrlibc driver.
-<code c>
-//
-// Simple up/down counting single 7-segment digit example.
-//
-// Raivo Sell, Erki Leitaru, Mikk Leini
-//
-// 2009
-//
-// Include avrlibc
-#include <avr/io.h>
-#include <util/delay.h>
-// Include common library
-#include "pinops.h"
-/* PS! For distance Lab use:
-#include <util/pinops.h>
-*/
-// Configure pins
-#define SEGMENT_DISPLAY_LATCH      PORTPIN(G, 2)
-#define SEGMENT_DISPLAY_DATA_OUT   PORTPIN(C, 6)
-#define SEGMENT_DISPLAY_CLOCK      PORTPIN(C, 7)
-//
-// 7 segment display initialization
-//
-void segment_display_init(void)
-{
-	// Set latch, data out and clock pins as output
-	setup_output_pin(SEGMENT_DISPLAY_LATCH);
-	setup_output_pin(SEGMENT_DISPLAY_DATA_OUT);
-	setup_output_pin(SEGMENT_DISPLAY_CLOCK);
-}
-//
-// Digit writing to 7 segment display
-//
-void segment_display_write(unsigned char digit)
-{
-	unsigned char map;
-	// Decimal to segment map
-	switch (digit)
-	{
-		case 0 : map = 0b00111111; break; // Every bit corresponds to one segment
-		case 1 : map = 0b00000110; break; // "1"
-		case 2 : map = 0b01011011; break; // "2"
-		case 3 : map = 0b01001111; break; // "3" and so on
-		case 4 : map = 0b01100110; break;
-		case 5 : map = 0b01101101; break;
-		case 6 : map = 0b01111100; break;
-		case 7 : map = 0b00000111; break;
-		case 8 : map = 0b01111111; break;
-		case 9 : map = 0b01100111; break;
-		default: map = 0b01111001;        // E like Error
-	}
-	// Latch low
-	clear_pin(SEGMENT_DISPLAY_LATCH);
-	// Send every bit in the byte. MSB (most significant bit) first.
-	for (signed char i = 7; i >= 0; i--)
-	{
-		// If bit is set, sets the data out pin, otherwise not
-		set_pin_to(SEGMENT_DISPLAY_DATA_OUT, IS_BIT_SET(map, i));
-		// Clock high for certain period
-		set_pin(SEGMENT_DISPLAY_CLOCK)
-		_delay_us(1);
-		// Clock low for certain period
-		clear_pin(SEGMENT_DISPLAY_CLOCK)
-		_delay_us(1);
-	}
-	// Latch high
-	set_pin(SEGMENT_DISPLAY_LATCH);
-}
-//
-// Program entrance function
-//
-int main(void)
-{
-	unsigned char digit = 0; // Digit to display on segment
-	signed char delta = 1;   // Digit modifying value
-	//digit = int (void) { return 2; };
-	// 7 segment display initialization
-	segment_display_init();
- 	// Endless loop
-	while (1)
-	{
-		// Write digit
-		segment_display_write(digit);
-		// Increase digit value by delta (which can be negative also)
-		digit += delta;
-		// Swap counting direction on 0 and 9
-		if (digit == 0) delta = +1;
-		if (digit == 9) delta = -1;
-		// Wait 1000 ms
-		_delay_ms(1000);
-	}
-}
-</code>
-===== External links =====
-[[http://en.wikipedia.org/wiki/Seven-segment_display|7-segment display in Wikipedia]]

en/examples/digi/7seg.1237962744.txt.gz · Last modified: 2020/07/20 09:00 (external edit)