add timer-supported software i2c + arduino-nano timer

8 files changed, 283 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 0771c1c..8baba0e 100644
--- a/Makefile
+++ b/Makefile
@@ -56,6 +56,11 @@ ifeq (${softi2c_pullup}, 1)
 	COMMON_FLAGS += -DSOFTI2C_PULLUP
 endif
 
+ifeq (${softi2c_timer}, 1)
+	arch_drivers += ,timer
+	COMMON_FLAGS += -DSOFTI2C_TIMER
+endif
+
 ifeq (${kout_nop}, 1)
 	COMMON_FLAGS += -DKOUT_NOP
 endif
diff --git a/include/arch/arduino-nano/driver/timer.h b/include/arch/arduino-nano/driver/timer.h
new file mode 100644
index 0000000..267cb1d
--- /dev/null
+++ b/include/arch/arduino-nano/driver/timer.h
@@ -0,0 +1,28 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+#define ON_TIMER_INTERRUPT ISR(TIMER0_COMPA_vect)
+
+class Timer {
+	private:
+		Timer(const Timer &copy);
+
+
+	public:
+		Timer() {}
+
+		inline void setup(unsigned char const frequency) {
+			OCR0A = frequency ? 255 / frequency : 1;
+			TCCR0A = _BV(WGM01);
+		}
+		inline void start(unsigned char const interrupt) {
+			TCNT0 = 0;
+			TCCR0B = _BV(CS01) | _BV(CS00);
+			if (interrupt) {
+				TIMSK0 = _BV(OCIE0A);
+			}
+		}
+		inline void stop() { TCCR0B = 0; TIMSK0 = 0; }
+};
+
+extern Timer timer;
diff --git a/src/arch/arduino-nano-168/Makefile.inc b/src/arch/arduino-nano-168/Makefile.inc
new file mode 100644
index 0000000..de4ac8b
--- /dev/null
+++ b/src/arch/arduino-nano-168/Makefile.inc
@@ -0,0 +1,74 @@
+# vim:ft=make
+
+MCU = atmega168
+PORT = /dev/ttyUSB0
+BAUD = 19200
+
+COMMON_FLAGS += -Werror=overflow
+COMMON_FLAGS += -mmcu=${MCU} -DF_CPU=16000000UL -DMULTIPASS_ARCH_arduino_nano
+COMMON_FLAGS += -flto
+COMMON_FLAGS += -DMULTIPASS_ARCH_HAS_I2C
+
+CC = avr-gcc
+CXX = avr-g++
+NM = avr-nm
+OBJCOPY = avr-objcopy
+OBJDUMP = avr-objdump
+
+ifeq (${aspectc}, 1)
+	CXX = ag++ -r build/repo.acp -v 0 --c_compiler avr-g++ -p . --Xcompiler
+endif
+
+TARGETS += src/arch/arduino-nano/arch.cc
+TARGETS += src/arch/arduino-nano/driver/gpio.cc
+TARGETS += src/arch/arduino-nano/driver/stdout.cc
+TARGETS += src/arch/arduino-nano/driver/uptime.cc
+
+ifneq ($(findstring softi2c,${drivers}), )
+else ifneq ($(findstring i2c,${arch_drivers}), )
+	TARGETS += src/arch/arduino-nano/driver/i2c.cc
+endif
+
+ifneq ($(findstring stdin,${arch_drivers}), )
+	TARGETS += src/arch/arduino-nano/driver/stdin.cc
+endif
+
+ifneq ($(findstring timer,${arch_drivers}), )
+	TARGETS += src/arch/arduino-nano/driver/timer.cc
+endif
+
+ifneq (${i2c_freq}, )
+	COMMON_FLAGS += -DF_I2C=${i2c_freq}
+endif
+
+ifneq (${timer_freq}, )
+	COMMON_FLAGS += -DF_TIMER=${timer_freq}
+endif
+
+OBJECTS = ${TARGETS:.cc=.o}
+
+.cc.o:
+	${CXX} ${INCLUDES} ${COMMON_FLAGS} ${CXXFLAGS} -c -o $@ ${@:.o=.cc}
+
+build/system.elf: ${OBJECTS}
+	${CXX} ${COMMON_FLAGS} ${CXXFLAGS} -Wl,--gc-sections -o $@ ${OBJECTS}
+	avr-size --format=avr --mcu=${MCU} $@
+
+build/system.hex: build/system.elf
+	${OBJCOPY} -O ihex ${@:.hex=.elf} $@
+
+program: build/system.hex
+	avrdude -p ${MCU} -c arduino -P ${PORT} -b ${BAUD} -U flash:w:build/system.hex
+
+arch_clean:
+	rm -f ${OBJECTS} build/system.hex
+
+monitor:
+	screen ${PORT} 115200
+
+arch_help:
+	@echo "arduino-nano specific flags:"
+	@echo "    PORT = ${PORT}"
+	@echo "    BAUD = ${BAUD} (only used for programming)"
+
+.PHONY: arch_clean arch_help monitor program
diff --git a/src/arch/arduino-nano-168/arch.cc b/src/arch/arduino-nano-168/arch.cc
new file mode 120000
index 0000000..808ad49
--- /dev/null
+++ b/src/arch/arduino-nano-168/arch.cc
@@ -0,0 +1 @@
+../arduino-nano/arch.cc
\ No newline at end of file
diff --git a/src/arch/arduino-nano-168/driver b/src/arch/arduino-nano-168/driver
new file mode 120000
index 0000000..d402f72
--- /dev/null
+++ b/src/arch/arduino-nano-168/driver
@@ -0,0 +1 @@
+../arduino-nano/driver
\ No newline at end of file
diff --git a/src/arch/arduino-nano/Makefile.inc b/src/arch/arduino-nano/Makefile.inc
index 18a6563..d4d5be7 100644
--- a/src/arch/arduino-nano/Makefile.inc
+++ b/src/arch/arduino-nano/Makefile.inc
@@ -4,6 +4,7 @@ MCU = atmega328p
 PORT = /dev/ttyUSB0
 BAUD = 57600
 
+COMMON_FLAGS += -Werror=overflow
 COMMON_FLAGS += -mmcu=${MCU} -DF_CPU=16000000UL -DMULTIPASS_ARCH_arduino_nano
 COMMON_FLAGS += -flto
 COMMON_FLAGS += -DMULTIPASS_ARCH_HAS_I2C
@@ -32,10 +33,18 @@ ifneq ($(findstring stdin,${arch_drivers}), )
 	TARGETS += src/arch/arduino-nano/driver/stdin.cc
 endif
 
+ifneq ($(findstring timer,${arch_drivers}), )
+	TARGETS += src/arch/arduino-nano/driver/timer.cc
+endif
+
 ifneq (${i2c_freq}, )
 	COMMON_FLAGS += -DF_I2C=${i2c_freq}
 endif
 
+ifneq (${timer_freq}, )
+	COMMON_FLAGS += -DF_TIMER=${timer_freq}
+endif
+
 OBJECTS = ${TARGETS:.cc=.o}
 
 .cc.o:
diff --git a/src/arch/arduino-nano/driver/timer.cc b/src/arch/arduino-nano/driver/timer.cc
new file mode 100644
index 0000000..4f2d6d1
--- /dev/null
+++ b/src/arch/arduino-nano/driver/timer.cc
@@ -0,0 +1,3 @@
+#include "driver/timer.h"
+
+Timer timer;
diff --git a/src/driver/soft_i2c.cc b/src/driver/soft_i2c.cc
index 33f77ab..99a88aa 100644
--- a/src/driver/soft_i2c.cc
+++ b/src/driver/soft_i2c.cc
@@ -2,6 +2,13 @@
 #include "driver/gpio.h"
 #include "arch.h"
 
+#ifdef SOFTI2C_TIMER
+#ifdef TIMER_CYCLES
+#error "SOFTI2C_TIMER and TIMER_CYCLES are mutually exclusive"
+#endif
+#include "driver/timer.h"
+#endif
+
 #ifdef SOFTI2C_PULLUP
 #define SDA_HIGH gpio.input(sda, 1)
 #define SDA_LOW gpio.output(sda, 0)
@@ -14,6 +21,8 @@
 #define SCL_LOW gpio.output(scl)
 #endif
 
+#ifndef SOFTI2C_TIMER
+
 signed char SoftI2C::setup()
 {
 	SDA_HIGH;
@@ -136,6 +145,159 @@ signed char SoftI2C::xmit(unsigned char address,
 	return 0;
 }
 
+#else
+
+#ifndef F_I2C
+#define F_I2C 100000
+#endif
+
+volatile unsigned char timer_done = 0;
+
+inline void await_timer()
+{
+	timer_done = 0;
+	timer.start(1);
+	while (!timer_done) {
+		arch.idle();
+	}
+	timer.stop();
+}
+
+signed char SoftI2C::setup()
+{
+	SDA_HIGH;
+	SCL_HIGH;
+	/*
+	 * I2C frequency is the time between two SCL low->high transitions
+	 * (or high->low, whatever you prefer). For the timer, we need to set the
+	 * time between SCL low->high and the following high->low transition
+	 * (and vice versa), which is twice the desired I2C frequency. Also,
+	 * timer.setup wants kHz and not Hz, so we have
+	 * Timer Freq [kHz] = I2C Freq [Hz] * 2 / 1000
+	 */
+	timer.setup(F_I2C / 500);
+	return 0;
+}
+
+void SoftI2C::start()
+{
+	SDA_HIGH;
+	SCL_HIGH;
+	await_timer();
+	SDA_LOW;
+	await_timer();
+	SCL_LOW;
+	await_timer();
+}
+
+void SoftI2C::stop()
+{
+	SCL_LOW;
+	SDA_LOW;
+	await_timer();
+	SCL_HIGH;
+	await_timer();
+	SDA_HIGH;
+}
+
+bool SoftI2C::tx(unsigned char byte)
+{
+	unsigned char got_ack = 0;
+	for (unsigned char i = 0; i <= 8; i++) {
+		if ((byte & 0x80) || (i == 8)) {
+			SDA_HIGH;
+		} else {
+			SDA_LOW;
+		}
+		byte <<= 1;
+		SCL_HIGH;
+		await_timer();
+		while (!gpio.read(scl)) ;
+		if (i == 8) {
+			if (!gpio.read(sda)) {
+				got_ack = 1;
+			}
+		}
+		SCL_LOW;
+		await_timer();
+	}
+	return got_ack;
+}
+
+unsigned char SoftI2C::rx(bool send_ack)
+{
+	unsigned char byte = 0;
+	SDA_HIGH;
+	for (unsigned char i = 0; i <= 8; i++) {
+		SCL_HIGH;
+		await_timer();
+		while (!gpio.read(scl)) ;
+		if ((i < 8) && gpio.read(sda)) {
+			byte |= 1 << (7 - i);
+		}
+		SCL_LOW;
+		await_timer();
+		if ((i == 7) && send_ack) {
+			SDA_LOW;
+		} else if ((i == 8) && send_ack) {
+			SDA_HIGH;
+		}
+	}
+	return byte;
+}
+
+void SoftI2C::scan(unsigned int *results)
+{
+	unsigned char i2caddr;
+	for (unsigned char address = 0; address < 128; address++) {
+
+		i2caddr = (address << 1) | 0;
+
+		start();
+
+		if (tx(i2caddr)) {
+			results[address / (8 * sizeof(unsigned int))] |= 1 << (address % (8 * sizeof(unsigned int)));
+			stop();
+		}
+	}
+	stop();
+}
+
+signed char SoftI2C::xmit(unsigned char address,
+		unsigned char tx_len, unsigned char *tx_buf,
+		unsigned char rx_len, unsigned char *rx_buf)
+{
+	unsigned char i;
+
+	if (tx_len) {
+		start();
+		tx((address << 1) | 0);
+
+		for (i = 0; i < tx_len; i++) {
+			tx(tx_buf[i]);
+		}
+	}
+	if (rx_len) {
+		start();
+		tx((address << 1) | 1);
+
+		for (i = 1; i <= rx_len; i++) {
+			rx_buf[i-1] = rx((i < rx_len) * 1);
+		}
+	}
+
+	stop();
+
+	return 0;
+}
+
+ON_TIMER_INTERRUPT
+{
+	timer_done = 1;
+}
+
+#endif
+
 #ifdef MULTIPASS_ARCH_esp8266
 SoftI2C i2c(GPIO::d7, GPIO::d8);
 #elif MULTIPASS_ARCH_arduino_nano