ST72321AR6-Auto STMicroelectronics, ST72321AR6-Auto Datasheet - Page 158

• Manufacturer Part Number: ST72321AR6-Auto
• Description: 8-bit MCU for automotive with 32 Kbyte Flash, 10-bit ADC, timers, SPI, SCI and I2C interfaces
• Manufacturer: STMicroelectronics

Specifications of ST72321AR6-Auto

• Hdflash Endurance: 100 cycles, data retention 20 years
• Clock Sources: crystal/ceramic resonator oscillators, internal RC oscillator and bypass for external clock
• 4 Power Saving Modes: Halt, Active Halt, Wait and Slow

I2C bus interface (I2C)
16.4
16.4.1
Note:
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Functional description
Refer to the CR, SR1 and SR2 registers in
By default the I
initiates a transmit or receive sequence.
First the interface frequency must be configured using the FRi bits in the OAR2 register.
Slave mode
As soon as a start condition is detected, the address is received from the SDA line and sent
to the shift register; then it is compared with the address of the interface or the General Call
address (if selected by software).
In 10-bit addressing mode, the comparison includes the header sequence (11110xx0) and
the two most significant bits of the address.
Header matched (10-bit mode only): The interface generates an acknowledge pulse if the
ACK bit is set.
Address not matched: The interface ignores it and waits for another Start condition.
Address matched: The interface generates in sequence:
●
●
Then the interface waits for a read of the SR1 register, holding the SCL line low (see
Figure 68: Transfer sequencing
Next, in 7-bit mode read the DR register to determine from the least significant bit (Data
Direction Bit) if the slave must enter Receiver or Transmitter mode.
In 10-bit mode, after receiving the address sequence the slave is always in receive mode. It
will enter transmit mode on receiving a repeated Start condition followed by the header
sequence with matching address bits and the least significant bit set (11110xx1).
Slave receiver
Following the address reception and after the SR1 register has been read, the slave
receives bytes from the SDA line into the DR register via the internal shift register. After
each byte the interface generates in sequence:
●
●
Then the interface waits for a read of the SR1 register followed by a read of the DR register,
holding the SCL line low (see
Slave transmitter
Following the address reception and after SR1 register has been read, the slave sends
bytes from the DR register to the SDA line via the internal shift register.
The slave waits for a read of the SR1 register followed by a write in the DR register, holding
the SCL line low (see
When the acknowledge pulse is received:
●
an acknowledge pulse if the ACK bit is set
EVF and ADSL bits are set with an interrupt if the ITE bit is set.
an acknowledge pulse if the ACK bit is set
EVF and BTF bits are set with an interrupt if the ITE bit is set.
The EVF and BTF bits are set by hardware with an interrupt if the ITE bit is set.
2
C interface operates in Slave mode (M/SL bit is cleared) except when it
Figure 68: Transfer sequencing
Doc ID 13829 Rev 1
EV1).
Figure 68: Transfer sequencing
Section 16.7
EV3).
for the bit definitions.
EV2).
ST72321xx-Auto