Merge remote-tracking branch 'upstream/master' into spi_bitbang

examples/board_rotenc/Makefile

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+#
+# 	Copyright 2008-2012 Michel Pollet <buserror@gmail.com>
+# 	Copyright 2018 Doug Szumski <d.s.szumski@gmail.com>
+#
+#	This file is part of simavr.
+#
+#	simavr is free software: you can redistribute it and/or modify
+#	it under the terms of the GNU General Public License as published by
+#	the Free Software Foundation, either version 3 of the License, or
+#	(at your option) any later version.
+#
+#	simavr is distributed in the hope that it will be useful,
+#	but WITHOUT ANY WARRANTY; without even the implied warranty of
+#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#	GNU General Public License for more details.
+#
+#	You should have received a copy of the GNU General Public License
+#	along with simavr.  If not, see <http://www.gnu.org/licenses/>.
+
+target=rotenc_test
+firm_src = ${wildcard at*${board}.c}
+firmware = ${firm_src:.c=.axf}
+simavr = ../..
+
+IPATH = .
+IPATH += ${simavr}/examples/shared
+IPATH += ${simavr}/examples/parts
+IPATH += ${simavr}/include
+IPATH += ${simavr}/simavr/sim
+
+VPATH = .
+VPATH += ${simavr}/examples/shared
+VPATH += ${simavr}/examples/parts
+
+LDFLAGS += -lpthread
+
+include ../Makefile.opengl
+
+all: obj ${firmware} ${target}
+
+include ${simavr}/Makefile.common
+
+atmega1280_${target}.axf: atmega32_${target}.c
+
+board = ${OBJ}/${target}.elf
+
+${board} : ${OBJ}/${target}.o
+${board} : ${OBJ}/rotenc.o
+
+${target}: ${board}
+	@echo $@ done
+
+clean: clean-${OBJ}
+	rm -rf *.hex *.a *.axf ${target} *.vcd .*.swo .*.swp .*.swm .*.swn

examples/board_rotenc/README

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+board_rotenc
+
+This sample code demonstrates the use of a virtual Panasonic EVEP rotary
+encoder. The encoder is hooked up to an LED array, and is used to scroll
+an LED up and down. It behaves just like in real life, except contact
+bounce is not modelled.

examples/board_rotenc/atmega32_rotenc_test.c

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+/*
+ atmega32_rotenc_test.c
+
+ A simple example demonstrating a Pansonic EVEP rotary encoder
+ scrolling an LED up and down an 8 segment LED bar.
+
+ Copyright 2018 Doug Szumski <d.s.szumski@gmail.com>
+
+ This file is part of simavr.
+
+ simavr is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ simavr is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with simavr.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/sleep.h>
+#include <stdio.h>
+
+#include "avr_mcu_section.h"
+AVR_MCU(F_CPU, "atmega32");
+
+typedef enum {
+	CLOCKWISE,
+	COUNTERCLOCKWISE
+} led_scroll_dir_t;
+
+/* Initialise the inputs for signal A and signal B from the rotary encoder.
+ * They are hooked up to INTO on PD2 and GPIO pin PA0. Pull-ups are on the
+ * PCB. */
+void
+rotary_spin_int_init(void)
+{
+	// Set INT0 and GPIO pin as inputs
+	DDRD &= ~(1 << PD2) & ~(1 << PA0);
+	// Any logical change on INT0 generates an interrupt (see DS p.67)
+	MCUCR |= (1 << ISC00);
+	MCUCR &= ~(1 << ISC01);
+	// Enable interrupt pin PD2
+	GICR |= (1 << INT0);
+}
+
+/* Initialise inputs for signal C from the rotary encoder (button). This
+ * is hooked up to INT2 on PB2. A pull-up is on the PCB. */
+void
+rotary_button_int_init(void)
+{
+	DDRB &= ~(1 << PB2);
+	// Falling edge trigger (pin is pulled up) (see DS p.67)
+	MCUCSR &= ~(1 << ISC2);
+	// Enable interrupt pin PB2
+	GICR |= (1 << INT2);
+}
+
+/* Configure 8 segment virtual 'LED bar' on port C */
+void
+led_bar_init(void)
+{
+	DDRC = 0xFF; // All outputs
+	PORTC = 0b00010000; // Start with a light on in the middle
+}
+
+void
+led_bar_scroll(led_scroll_dir_t dir)
+{
+	switch (dir) {
+		case CLOCKWISE:
+			if (PORTC < 0b10000000) PORTC <<= 1;
+			break;
+		case COUNTERCLOCKWISE:
+			if (PORTC > 0b00000001) PORTC >>= 1;
+			break;
+		default:
+			break;
+	}
+}
+
+int
+main()
+{
+	// Disable interrupts whilst configuring them to avoid false triggers
+	cli();
+	rotary_spin_int_init();
+	rotary_button_int_init();
+	sei();
+
+	led_bar_init();
+
+	while (1) {
+		// Wait for some input
+	}
+
+	cli();
+	sleep_mode();
+}
+
+ISR(INT0_vect)
+{
+	// The Panasonic EVEP rotary encoder this is written for moves two
+	// phases for every 'click' it emits. The interrupt is configured
+	// to fire on every edge change of B, which is once per 'click'.
+	// Moving forwards in phase, after B has changed state we poll A.
+	// We get the sequence (A=0,B=1), (A=1,B=0). Moving backwards in
+	// phase, after B has changed state we get (A=1,B=1), (A=0,B=0).
+	//
+	// +-------+---+---+
+	// | Phase | A | B |
+	// +-------+---+---+
+	// |   0   | 0 | 0 |
+	// |   1   | 0 | 1 |
+	// |   2   | 1 | 1 |
+	// |   3   | 1 | 0 |
+	// +-------+---+---+
+	//
+	// The twist direction is then obtained by taking the logical
+	// XOR of outputs A and B after the interrupt has fired. Of
+	// course with a 'real life' part you might be better off
+	// using a state machine, or some extra hardware to filter out
+	// contact bounces which aren't modelled in the virtual part.
+	uint8_t ccw_twist = ((PIND & (1 << PD2)) >> 2) ^ (PINA & (1 << PA0));
+
+	// Scroll the LED bar
+	if (ccw_twist) {
+		led_bar_scroll(COUNTERCLOCKWISE);
+	} else {
+		led_bar_scroll(CLOCKWISE);
+	}
+}
+
+ISR(INT2_vect)
+{
+	// Fires when rotary encoder button was pressed and resets
+	// the LED bar to the starting position
+	PORTC = 0b00010000;
+}