iicbus(4) [linux man page]
IICBUS(4) BSD Kernel Interfaces Manual IICBUS(4) NAME
iicbus -- I2C bus system SYNOPSIS
device iicbus device iicbb device iic device ic device iicsmb DESCRIPTION
The iicbus system provides a uniform, modular and architecture-independent system for the implementation of drivers to control various I2C devices and to utilize different I2C controllers. I2C I2C is an acronym for Inter Integrated Circuit bus. The I2C bus was developed in the early 1980's by Philips semiconductors. Its purpose was to provide an easy way to connect a CPU to peripheral chips in a TV-set. The BUS physically consists of 2 active wires and a ground connection. The active wires, SDA and SCL, are both bidirectional. Where SDA is the Serial DAta line and SCL is the Serial CLock line. Every component hooked up to the bus has its own unique address whether it is a CPU, LCD driver, memory, or complex function chip. Each of these chips can act as a receiver and/or transmitter depending on its functionality. Obviously an LCD driver is only a receiver, while a memory or I/O chip can both be transmitter and receiver. Furthermore there may be one or more BUS MASTERs. The BUS MASTER is the chip issuing the commands on the BUS. In the I2C protocol specification it is stated that the IC that initiates a data transfer on the bus is considered the BUS MASTER. At that time all the others are regarded to as the BUS SLAVEs. As mentioned before, the IC bus is a Multi-MASTER BUS. This means that more than one IC capable of initiating data transfer can be connected to it. DEVICES
Some I2C device drivers are available: Devices Description iic general i/o operation ic network IP interface iicsmb I2C to SMB software bridge INTERFACES
The I2C protocol may be implemented by hardware or software. Software interfaces rely on very simple hardware, usually two lines twiddled by 2 registers. Hardware interfaces are more intelligent and receive 8-bit characters they write to the bus according to the I2C protocol. I2C interfaces may act on the bus as slave devices, allowing spontaneous bidirectional communications, thanks to the multi-master capabili- ties of the I2C protocol. Some I2C interfaces are available: Interface Description pcf Philips PCF8584 master/slave interface iicbb generic bit-banging master-only driver lpbb parallel port specific bit-banging interface bktr Brooktree848 video chipset, hardware and software master-only interface SEE ALSO
iicbb(4), lpbb(4), pcf(4) HISTORY
The iicbus manual page first appeared in FreeBSD 3.0. AUTHORS
This manual page was written by Nicolas Souchu. BSD
August 6, 1998 BSD
Check Out this Related Man Page
IIC(4) BSD Kernel Interfaces Manual IIC(4) NAME
iic -- Inter IC (I2C) bus SYNOPSIS
iic* at alipm? # sparc64 iic* at acpismbus? # amd64 i386 iic* at amdpm? # amd64 i386 iic* at armadillo9iic? # evbarm iic0 at at91twi? # evbarm iic0 at ausmbus0 # evbmips iic0 at cuda0 # macppc iic0 at gpiic? # evbppc iic* at gpioiic? # amd64 i386 iic* at gtiic? # evbppc iic* at gxiic? # evbarm iic* at ichsmb? # amd64 i386 iic0 at iociic0 # acorn26 iic0 at iomdiic? # acorn32 iic0 at iopiic? # evbarm iyonix iic* at ki2c? # macppc iic* at nfsmb? # amd64 i386 iic* at ociic? # sandpoint iic* at piixpm? # amd64 i386 iic0 at slugiic0 # evbarm iic* at viapcib? # i386 DESCRIPTION
I2C is a two-wire bus developed by Philips used for connecting integrated circuits. It is commonly used for connecting devices such as EEP- ROMs, temperature sensors, fan controllers, real-time clocks, tuners, and other types of integrated circuits. The iic driver provides a uniform programming interface layer between I2C master controllers and various I2C slave devices. Each I2C master controller attaches an iic framework; several slave devices can then be attached to the iic bus. All I2C slave devices are uniquely identified by the address on the bus. The master accesses a particular slave device using its address. System Management Bus (SMBus) protocol is also supported by emulating it with the I2C commands. SUPPORTED MASTERS
A wide list of I2C masters are supported, among them are: alipm(4) Acer Labs M7101 SMBus controller acpismbus(4) ACPI SMBus Control Method Interface amdpm(4) AMD768 Power Management Controller and AMD8111 System Management Controller armadillo9iic(4) at91twi(4) ausmbus(4) cuda(4) support for CUDA microcontrollers found in many Power Macintosh and and compatible computers gpiic(4) gtiic(4) gxiic(4) ichsmb(4) Intel ICH SMBus controller iociic(4) iomdiic(4) iopiic(4) ki2c(4) gpioiic(4) GPIO bit-banging nfsmb(4) NVIDIA nForce 2/3/4 SMBus controller and SMBus driver ociic(4) piixpm(4) Intel PIIX and compatible Power Management controller slugiic(4) viapcib(4) SUPPORTED SLAVES
A wide list of slaves are supported, among them: dbcool(4) dbCool(tm) family of environmental monitors and fan controllers rs5c372rtc(4) RICOH RS5C372A and RS5C372B real-time clock sgsmix(4) driver for SGS 7433 Basic Audio Processor found in some Apple machines spdmem(4) Generic Memory Module Serial Presence Detect SEE ALSO
dtviic(4), intro(4), i2cscan(8), iic(9) HISTORY
The I2C framework first appeared in NetBSD 2.0. OpenBSD support was added in OpenBSD 3.6. This manpage first appeared in NetBSD 6.0, it was ported from OpenBSD. AUTHORS
The I2C framework was written by Steve C. Woodford and Jason R. Thorpe for NetBSD and then ported to OpenBSD by Alexander Yurchenko <grange@openbsd.org>. BSD
October 15, 2011 BSD