An I2C library for Arduboy multiplayer games. More...

#include <avr/interrupt.h>
#include <avr/power.h>
#include <util/twi.h>
#include <stdint.h>
#include <stddef.h>

Classes
class	I2C

Macros
#define	I2C_FREQUENCY 100000
	The initial I2C frequency.

#define	I2C_BUFFER_SIZE 32
	The size of the buffer used for writes/target (slave) operations.

#define	I2C_BUS_BUSY_CHECKS 16
	The amount of times the bus is checked before continuing with a read/write operation.

#define	I2C_SCL_PIN PIND
	The pin on which the SCL line is connected.

#define	I2C_SCL_BIT PIND0
	The bit of the pin on which the SCL line is connected.

#define	I2C_SDA_PIN PIND
	The pin on which the SDA line is connected.

#define	I2C_SDA_BIT PIND1
	The bit of the pin on which the sda line is connected.

#define	I2C_MAX_PLAYERS
	The maxmimum number of players in the handshake/lobby.

#define	I2C_CUSTOM_HANDSHAKE
	When defined, removes overhead for handshaking included when I2C_MAX_PLAYERS is defined.

#define	TW_SUCCESS 0xFF
	Error code used to mean success, returned by I2C::getTWError().

#define	I2C_HANDSHAKE_FAILED 0xFE
	Error code RETURNED by I2C::handshake, meaning the handshake has already been completed.

#define	I2C_MAX_ADDRESSES 112
	The maximum amount of addresses available to a device.

#define	I2C_LIB_VER 20102
	I2C library version.

Detailed Description

An I2C library for Arduboy multiplayer games.

Macro Definition Documentation

◆ I2C_BUFFER_SIZE

#define I2C_BUFFER_SIZE 32

The size of the buffer used for writes/target (slave) operations.

Defaults to 32. If more than 32 bytes are needed for writes/target (slave) operations, increase. If more RAM is needed, decrease.

◆ I2C_BUS_BUSY_CHECKS

#define I2C_BUS_BUSY_CHECKS 16

The amount of times the bus is checked before continuing with a read/write operation.

Defaults to 16. Fixes design flaw where TWI hardware does not check if the bus has become busy during a stop interrupt, so if multiple targets (slaves) receive the stop interrupt right before they become the controller (master) and send a start, they all will think the bus is free and clobber each other. Can be set to 0 when there is only one controller (master). Increase if the game ever freezes. More information: https://www.robotroom.com/Atmel-AVR-TWI-I2C-Multi-Master-Problem.html

◆ I2C_FREQUENCY

#define I2C_FREQUENCY 100000

The initial I2C frequency.

Defaults to 100000 Hz.
Standard frequencies:
100000 Hz - Standard Mode
400000 Hz - Fast Mode

◆ I2C_LIB_VER

#define I2C_LIB_VER 20102

I2C library version.

For a given version x.y.z, the library version will be in the form xxxyyzz with no leading zeros on x.

◆ I2C_MAX_ADDRESSES

#define I2C_MAX_ADDRESSES 112

The maximum amount of addresses available to a device.

I2C uses a 7-bit addressing scheme with 127 available unique addresses. However, addresses 0-7 and 120-127 are reserved by the standard and should not be used. This leaves 112 addresses for devices to use.

◆ I2C_MAX_PLAYERS

#define I2C_MAX_PLAYERS

The maxmimum number of players in the handshake/lobby.

Cannot be more than I2C_MAX_ADDRESSES.

◆ I2C_SCL_BIT

#define I2C_SCL_BIT PIND0

The bit of the pin on which the SCL line is connected.

Defaults to PIND0.

◆ I2C_SCL_PIN

#define I2C_SCL_PIN PIND

The pin on which the SCL line is connected.

Defaults to PIND.

◆ I2C_SDA_BIT

#define I2C_SDA_BIT PIND1

The bit of the pin on which the sda line is connected.

Defaults to PIND1.

◆ I2C_SDA_PIN

#define I2C_SDA_PIN PIND

The pin on which the SDA line is connected.