Bus interface STw8009/STw8019
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Figure 18. 2-wire serial MPU control interface format (I2C compatible) / 7-bit addresses
10 bits address mode
In Write mode, sev er al data can be sent without re-initializing a transf er, in this case, data is
written in successive registers. (
Figure 19: 2-wire serial MPU control interface format (I2C
compatible) / 10-bit addresses
)
In Read mode: (
Figure 19
)
●Double transaction read:
The operation is split into two transactions:
The first one is a write that transmits the desired address. The I2C interface memorizes
the address of the register.
The second transfer is a read that can be repeated to read successive registers. After
each read byte and except for the last one, the master issues an “acknowledge”. The
master indicates that it is reading the last byte by issuing a “no acknowledge” instead of
an “acknowledge”.
Note: Only the higher part of the address is sent again before sending the read indication.
●Single transaction read:
As opposed to the double transaction, instead of stopping the first transaction and
starting the second one, the transactions are combined with a repeated start condition.
S STw8009 slave address r/w ASTw8009 register address A
Write (0)
* Write operation (7 bits addresses)
SStart condition PStop condi tion A/NA Acknowledge / No Acknoledge
PSTw8009 register data A
Can be repeated n times to write in successive registers
From mas ter to s lave From slave to master
S STw8009 slave address r/w ASTw8009 register address A P
Write (0)
* Double transaction read
S STw8009 slave address r/w ASTw8009 register data A/NA P
Read (1) Can be repeated n times to read in successive registers
Sr Repeated start condition
S STw8009 slave address r/w ASTw8009 register address A
Write (0)
* Single transaction read
STw8009 register data P
Can be repeated n times
to read in successive registers
Sr STw8009 slave address r/w
Read (1)
A/NA
S STw8009 slave address r/w ASTw8009 register address A
Write (0)
* Write operation (7 bits addresses)
SStart condition PStop condi tion A/NA Acknowledge / No Acknoledge
PSTw8009 register data A
Can be repeated n times to write in successive registers
From mas ter to s lave From slave to master
S STw8009 slave address r/w ASTw8009 register address A P
Write (0)
* Double transaction read
S STw8009 slave address r/w ASTw8009 register data A/NA P
Read (1) Can be repeated n times to read in successive registers
Sr Repeated start condition
S STw8009 slave address r/w ASTw8009 register address A
Write (0)
* Single transaction read
STw8009 register data P
Can be repeated n times
to read in successive registers
Sr STw8009 slave address r/w
Read (1)
A/NA