hello everyone

today we're going to talk about SM bus

SM bus is also called System Management Bus

it was proposed by Intel in 1995

it is a serial bus consisting of 2 wires

these 2 lines are a clock line

and the other is called a data line

this bus is wildly used for low rate

signal communication

in notebook computers and desktop motor boards

commonly

used to control the devices on the motor board

and collect a related device information

for example

PCH can read memory information through SM bus

this V form can be measured on SM bus

when PCH is reading memory information

on collecting external device information

in this waveform

the above group of relatively regular high and low

levels is the clock signal

which is SMB CLK

the following group is an irregular high and low level

this one is data called SMB d a t a

EC also has a system management bus

the SM bus of EC

is usually used to obtain battery power information

temperature information of temperature control circuit

etc

at the same time

it will also participate

in the control of some circuit devices

for example

through SM bus to control the charging chip work

it will also obtain the

identity information of other chips through SM bus

for example touch chip

or the identity

signal and data transmission

of the ambient light sensor chip

in their control relationship

they are the subordination relationship

EC or PCH is the superior

control circuits such as batteries and charging chips

are support knits

and this is their subordination relationship

this is the SM bus