Add Software I2C implementation

	COMMON_FLAGS += -DSHARP96_CS_PIN=GPIO::${sharp96_cs_pin}

endif

ifneq ($(findstring softi2c,${drivers}), )

	TARGETS += src/driver/soft_i2c.cc

	COMMON_FLAGS += -DDRIVER_SOFTI2C

endif

ifeq (${timer_cycles}, 1)

	COMMON_FLAGS += -DTIMER_CYCLES

endif

#ifndef SOFTI2C_H

#define SOFTI2C_H

class SoftI2C {

	private:

		SoftI2C(const SoftI2C &copy);

		unsigned char sda, scl;

		void start();

		void stop();

		bool tx(unsigned char byte);

		unsigned char rx(bool send_ack);

	public:

		SoftI2C(unsigned char sda, unsigned char scl) : sda(sda), scl(scl) {}

		signed char setup();

		void scan(unsigned int *results);

		signed char xmit(unsigned char address,

				unsigned char tx_len, unsigned char *tx_buf,

				unsigned char rx_len, unsigned char *rx_buf);

};

extern SoftI2C i2c;

#endif

#include "driver/soft_i2c.h"

#include "driver/gpio.h"

signed char SoftI2C::setup()

{

	gpio.write(sda, 0);

	gpio.write(scl, 0);

	return 0;

}

void SoftI2C::start()

{

	gpio.input(sda);

	gpio.input(scl);

	//

	gpio.output(sda);

	//

	gpio.output(scl);

}

void SoftI2C::stop()

{

	gpio.output(sda);

	//

	gpio.input(scl);

	//

	gpio.input(sda);

}

bool SoftI2C::tx(unsigned char byte)

{

	unsigned char got_ack = 0;

	for (unsigned char i = 0; i <= 8; i++) {

		if ((byte & 0x80) || (i == 8)) {

			gpio.input(sda);

		} else {

			gpio.output(sda);

		}

		byte <<= 1;

		//

		gpio.input(scl);

		//

		if (i == 8) {

			if (!gpio.read(sda)) {

				got_ack = 1;

			}

		}

		gpio.output(scl);

		//

	}

	return got_ack;

}

unsigned char SoftI2C::rx(bool send_ack)

{

	unsigned char byte = 0;

	gpio.input(sda);

	for (unsigned char i = 0; i <= 8; i++) {

		//

		gpio.input(scl);

		//

		if ((i < 8) && gpio.read(sda)) {

			byte |= 1 << (7 - i);

		}

		//

		gpio.output(scl);

		//

		if ((i == 7) && send_ack) {

			gpio.output(sda);

		} else if ((i == 8) && send_ack) {

			gpio.input(sda);

		}

	}

	return byte;

}

void SoftI2C::scan(unsigned int *results)

{

	unsigned char i2caddr;

	for (unsigned char address = 0; address < 128; address++) {

		i2caddr = (address << 1) | 1;

		start();

		if (tx(i2caddr)) {

			results[address / (8 * sizeof(unsigned int))] |= 1 << (address % (8 * sizeof(unsigned int)));

		}

	}

	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] = rx((i < rx_len) * 1);

		}

	}

	stop();

	return 0;

}

SoftI2C i2c(GPIO::p1_6, GPIO::p1_7);