optimise I2C

eeprom.cpp

@@ -33,10 +33,6 @@ static void set_address(uint8_t i2c_addr, uint16_t at) {
 	mem.write(at);
 }
 
-void eeprom::init() {
-	mem.begin();
-}
-
 void eeprom::jump(uint32_t p_at) {
 	last_block_end = 0;
 	at = p_at;

eeprom.hpp

@@ -12,7 +12,6 @@ namespace eeprom {
 
 	inline SoftTWI mem(A4, A5);
 
-	void init();
 	void jump(uint32_t addr);
 	void read(char* data, uint16_t len);
 	void page_write(uint32_t at, const char* data);

port.hpp

@@ -0,0 +1,69 @@
+
+#pragma once
+
+#include "util.hpp"
+
+namespace port {
+	struct Drain {
+		uint8_t mask;
+		uint8_t imask;
+		volatile uint8_t* mode;
+		volatile uint8_t* in;
+	
+		inline Drain(unsigned pin) AW_IN {
+			mask = digitalPinToBitMask(pin);
+			mode = portModeRegister(digitalPinToPort(pin));
+			in = portInputRegister(digitalPinToPort(pin));
+			imask = ~mask;
+		}
+	
+		inline void set(uint8_t b) AW_IN {
+			if(b) {
+				*mode &= imask;
+			} else {
+				*mode |= mask;
+			}
+		}
+	
+		inline uint8_t get() AW_IN {
+			return *in & mask;
+		}
+	};
+	
+	struct Input {
+		uint8_t mask;
+		uint8_t imask;
+		volatile uint8_t* in;
+	
+		inline Input(unsigned pin) AW_IN {
+			mask = digitalPinToBitMask(pin);
+			in = portInputRegister(digitalPinToPort(pin));
+			imask = ~mask;
+		}
+	
+		inline uint8_t get() AW_IN {
+			return *in & mask;
+		}
+	};
+	
+	struct Output {
+		uint8_t mask;
+		uint8_t imask;
+		volatile uint8_t* out;
+	
+		inline Output(unsigned pin) AW_IN {
+			mask = digitalPinToBitMask(pin);
+			out = portOutputRegister(digitalPinToPort(pin));
+			imask = ~mask;
+		}
+		
+		inline void set(uint8_t b) AW_IN {
+			if(b) {
+				*out |= mask;
+			} else {
+				*out &= imask;
+			}
+		}
+	};
+};
+

soft_twi.cpp

@@ -1,42 +1,53 @@
 
-#include "soft_twi.hpp"
 #include <Arduino.h>
-
+#include "soft_twi.hpp"
-void SoftTWI::set_pin(uint8_t pin, bool state)  {
+#include "port.hpp"
-	uint8_t bitmask = digitalPinToBitMask(pin);
-	volatile uint8_t* reg = portModeRegister(digitalPinToPort(pin));
-	if(state) {
-		*reg &= ~bitmask;
-	} else {
-		*reg |= bitmask;
-	}
-}
-
-void SoftTWI::begin() {
-	digitalWrite(_sda, 0);
-	digitalWrite(_scl, 0);
-}
-
-bool SoftTWI::read_pin(uint8_t pin) {
-	return digitalRead(pin);
-}
 
 uint8_t SoftTWI::read(bool ack) {
+	port::Drain sda(_sda);
+	port::Drain scl(_scl);
+
 	uint8_t v = 0;
 	for(unsigned m = 0x80; m; m >>= 1) {
-		if(read_bit()) {
+		sda.set(1);
+		scl.set(1);
+		while(!scl.get()) {}
+		if(sda.get()) {
 			v |= m;
 		}
+		scl.set(0);
 	}
-	write_bit(!ack); // send ACK
+	
+	// send ACK
+	if(ack) {
+		sda.set(!ack);
+		scl.set(1);
+		while(!scl.get()) {}
+		scl.set(0);
+	}
+
 	return v;
 }
 
 bool SoftTWI::write(uint8_t v) {
+	port::Drain sda(_sda);
+	port::Drain scl(_scl);
+
 	for(unsigned m = 0x80; m; m >>= 1) {
-		write_bit(v & m);
+		sda.set(v & m);
+		scl.set(1);
+		while(!scl.get()) {}
+		scl.set(0);
 	}
-	return !read_bit(); // get ACK
+
+	// get ACK
+	sda.set(1);
+	scl.set(1);
+	while(!scl.get()) {}
+	uint8_t s = sda.get();
+	scl.set(0);
+
+	return !s;
 }
 
 void SoftTWI::read(uint8_t* data, unsigned data_len, bool nack_at_end) {
@@ -54,3 +65,21 @@ unsigned SoftTWI::write(const uint8_t* data, unsigned data_len) {
 	return data_len;
 }
 
+bool SoftTWI::start(uint8_t addr) {
+	port::Drain sda(_sda);
+	port::Drain scl(_scl);
+	sda.set(1);
+	scl.set(1);
+	sda.set(0);
+	scl.set(0);
+	write(addr);
+}
+
+void SoftTWI::end() {
+	port::Drain sda(_sda);
+	port::Drain scl(_scl);
+	sda.set(0);
+	scl.set(1);
+	sda.set(1);
+}
+

soft_twi.hpp

@@ -6,115 +6,29 @@
 
 struct SoftTWI {
 	
-	constexpr SoftTWI(unsigned sda, unsigned scl, unsigned delay = 0);
+	constexpr SoftTWI::SoftTWI(unsigned sda, unsigned scl)
+		: _sda(sda)
+		, _scl(scl) {
+	}
 
-	void begin();
-	inline void sleep(uint8_t=1) AW_IN {}
-	inline void wait_scl() AW_IN;
-	
-	void set_pin(uint8_t, bool);
-	inline void set_sda(bool) AW_IN;
-	inline void set_scl(bool) AW_IN;
-	
-	bool read_pin(uint8_t);
-	inline bool read_sda() AW_IN;
-	inline bool read_scl() AW_IN;
-
-	inline void write_bit(bool) AW_IN;
-	bool write(uint8_t);
 	unsigned write(const uint8_t*, unsigned);
-	
-	inline bool read_bit() AW_IN;
-	uint8_t read(bool=true);
 	void read(uint8_t*, unsigned, bool=false);
+	uint8_t read(bool=true);
+	bool write(uint8_t);
+	void end();
 	
-	inline bool start_read(uint8_t) AW_IN;
+	inline bool start_read(uint8_t addr) {
-	inline bool start_write(uint8_t) AW_IN;
+		return start((addr << 1) | 1);
+	}
 
-	inline void start() AW_IN;
+	inline bool start_write(uint8_t addr) {
-	inline void end() AW_IN;
+		return start(addr << 1);
+	}
 	
 private:
 	unsigned _sda;
 	unsigned _scl;
-	unsigned _delay;
+	
+	bool start(uint8_t addr);
 };
 
-constexpr SoftTWI::SoftTWI(unsigned sda, unsigned scl, unsigned delay)
-	: _sda(sda)
-	, _scl(scl)
-	, _delay(delay) {
-}
-
-inline void SoftTWI::set_sda(bool s) {
-	set_pin(_sda, s);
-}
-
-inline void SoftTWI::set_scl(bool s) {
-	set_pin(_scl, s);
-}
-
-inline bool SoftTWI::read_sda() {
-	return read_pin(_sda);
-}
-
-inline bool SoftTWI::read_scl() {
-	return read_pin(_scl);
-}
-
-inline void SoftTWI::wait_scl() {
-	while(!read_pin(_scl)) {}
-}
-
-inline bool SoftTWI::read_bit() {
-	set_sda(1);
-	sleep();
-	set_scl(1);
-	sleep(2);
-	wait_scl();
-	bool s = read_sda();
-	set_scl(0);
-	sleep();
-	return s;
-}
-
-inline void SoftTWI::write_bit(bool s) {
-	set_sda(s);
-	sleep();
-	set_scl(1);
-	sleep(2);
-	wait_scl();
-	set_scl(0);
-	sleep();
-}
-
-inline void SoftTWI::start() {
-	set_sda(1);
-	sleep();
-	set_scl(1);
-	sleep();
-	set_sda(0);
-	sleep();
-	set_scl(0);
-	sleep();
-}
-
-inline void SoftTWI::end() {
-	set_sda(0);
-	sleep();
-	set_scl(1);
-	sleep();
-	set_sda(1);
-	sleep(2);
-}
-
-inline bool SoftTWI::start_read(uint8_t addr) {
-	start();
-	return write((addr << 1) | 1);
-}
-
-inline bool SoftTWI::start_write(uint8_t addr) {
-	start();
-	return write(addr << 1);
-}
-

tone-generator.ino

@@ -25,7 +25,6 @@ void setup() {
   Tone::init();
 	dac::init();
   serial::init();
-  eeprom::init();
   tones::init();
   indicator::init();
   buttons::init();