A96G150 User's manual
15. Combination of USART, SPI, and I2C (USI)
199
15.18
USIn I2C synchronization/arbitration
Clock synchronization is performed using the wired-AND connection of I2C interfaces to the SCLn line.
This means that a HIGH to LOW transition on the SCLn line will cause the devices concerned to start
counting off their LOW period and it will hold the SCLn line in that state until the clock HIGH state is
reached. However the LOW to HIGH transition of this clock may not change the state of the SCLn line
if another clock is still within its LOW period. In this way, a synchronized SCLn clock is generated with
its LOW period determined by the device with the longest clock LOW period, and its HIGH period
determined by the one with the shortest clock HIGH period.
A master may start a transfer only if the bus is free. Two or more masters may generate a START
condition. Arbitration takes place on the SDAn line, while the SCLn line is at the HIGH level, in such a
way that the master which transmits a HIGH level, while another master is transmitting a LOW level will
switch off its DATA output state because the level on the bus doesn’t correspond to its own level.
Arbitration continues for many bits until a winning master gets the ownership of I2C bus. Its first stage
is comparison of the address bits.
Figure 94. Clock Synchronization during Arbitration Procedure (USIn)
Figure 95. Arbitration Procedure of Two Masters (USIn)
High Counter Reset
Fast Device SCLOUT
Slow Device SCLOUT
SCLn
Wait High
Counting
Start High
Counting
Device1
Data Out
SCLn on
BUS
Device2
Data Out
SDAn on
BUS
S
Arbitration Process
not adapted
Device 1 loses
Arbitration
Device1 outputs
High
Содержание A96G150
Страница 126: ...12 Timer 0 1 2 3 4 5 A96G150 User s manual 126 Figure 43 16 bit Timer Counter Mode Operation Example...
Страница 136: ...12 Timer 0 1 2 3 4 5 A96G150 User s manual 136 Figure 51 16 bit Timer Counter Mode Operation Example...
Страница 147: ...A96G150 User s manual 12 Timer 0 1 2 3 4 5 147 Figure 59 16 bit Timer Counter Mode Operation Example...
Страница 157: ...A96G150 User s manual 12 Timer 0 1 2 3 4 5 157 Figure 67 16 bit Timer Counter Mode Operation Example...
Страница 171: ...A96G150 User s manual 14 12 bit ADC 171 Figure 79 ADC Operation Flow Sequence...
Страница 333: ...A96G150 User s manual Revision history 333 Revision history Revision Date Notes 1 00 2022 06 22 First creation...