I 2 C Status Register 2 (I2C_Sr2) - ST STM32F40 Series Reference Manual

Inter-integrated circuit (I
2
25.6.7 I C Status register 2 (I2C_SR2)
Address offset: 0x18
Reset value: 0x0000
Note: Reading I2C_SR2 after reading I2C_SR1 clears the ADDR flag, even if the ADDR flag was
set after reading I2C_SR1. Consequently, I2C_SR2 must be read only when ADDR is found
set in I2C_SR1 or when the STOPF bit is cleared.
15 14 13 12
r r r
Bits 15:8 PEC[7:0] Packet error checking register
Bit 7 DUALF: Dual flag (Slave mode)
Bit 6 SMBHOST: SMBus host header (Slave mode)
Bit 5 SMBDEFAULT: SMBus device default address (Slave mode)
Bit 4 GENCALL: General call address (Slave mode)
Bit 3 Reserved, must be kept at reset value
Bit 2 TRA: Transmitter/receiver
Bit 1 BUSY: Bus busy
737/1422
2
C) interface
11 10 9
PEC[7:0]
r r r r
This register contains the internal PEC when ENPEC=1.
0: Received address matched with OAR1
1: Received address matched with OAR2
–Cleared by hardware after a Stop condition or repeated Start condition, or when PE=0.
0: No SMBus Host address
1: SMBus Host address received when SMBTYPE=1 and ENARP=1.
–Cleared by hardware after a Stop condition or repeated Start condition, or when PE=0.
0: No SMBus Device Default address
1: SMBus Device Default address received when ENARP=1
–Cleared by hardware after a Stop condition or repeated Start condition, or when PE=0.
0: No General Call
1: General Call Address received when ENGC=1
–Cleared by hardware after a Stop condition or repeated Start condition, or when PE=0.
0: Data bytes received
1: Data bytes transmitted
This bit is set depending on the R/W bit of the address byte, at the end of total address
phase.
It is also cleared by hardware after detection of Stop condition (STOPF=1), repeated Start
condition, loss of bus arbitration (ARLO=1), or when PE=0.
0: No communication on the bus
1: Communication ongoing on the bus
–Set by hardware on detection of SDA or SCL low
–cleared by hardware on detection of a Stop condition.
It indicates a communication in progress on the bus. This information is still updated when
the interface is disabled (PE=0).
Doc ID 018909 Rev 4
8 7 6 5
SMB SMBDE
DUALF
HOST FAULT
r r r r
4 3 2 1
GEN
TRA BUSY
CALL
Res.
r r r
RM0090
0
MSL
r