STMicroelectronics RM0365 Reference Manual page 819

Inter-integrated circuit (I2C) interface
Bit 20 SMBHEN: SMBus Host address enable
Note: If the SMBus feature is not supported, this bit is reserved and forced by hardware to '0'.
Bit 19 GCEN: General call enable
Bit 18 WUPEN: Wakeup from Stop mode enable
Note: If the Wakeup from Stop mode feature is not supported, this bit is reserved and forced
Note: WUPEN can be set only when DNF = '0000'
Bit 17 NOSTRETCH: Clock stretching disable
This bit is used to disable clock stretching in slave mode. It must be kept cleared in master
mode.
Note: This bit can only be programmed when the I2C is disabled (PE = 0).
Bit 16 SBC: Slave byte control
This bit is used to enable hardware byte control in slave mode.
Bit 15 RXDMAEN: DMA reception requests enable
Bit 14 TXDMAEN: DMA transmission requests enable
Bit 13 Reserved, must be kept at reset value.
Bit 12 ANFOFF: Analog noise filter OFF
Note: This bit can only be programmed when the I2C is disabled (PE = 0).
Bits 11:8 DNF[3:0]: Digital noise filter
These bits are used to configure the digital noise filter on SDA and SCL input. The digital filter
will filter spikes with a length of up to DNF[3:0] * t
Note: If the analog filter is also enabled, the digital filter is added to the analog filter.
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0: Host address disabled. Address 0b0001000x is NACKed.
1: Host address enabled. Address 0b0001000x is ACKed.
Please refer to Section 28.3: I2C
0: General call disabled. Address 0b00000000 is NACKed.
1: General call enabled. Address 0b00000000 is ACKed.
0: Wakeup from Stop mode disable.
1: Wakeup from Stop mode enable.
by hardware to '0'. Please refer to
0: Clock stretching enabled
1: Clock stretching disabled
0: Slave byte control disabled
1: Slave byte control enabled
0: DMA mode disabled for reception
1: DMA mode enabled for reception
0: DMA mode disabled for transmission
1: DMA mode enabled for transmission
0: Analog noise filter enabled
1: Analog noise filter disabled
0000: Digital filter disabled
0001: Digital filter enabled and filtering capability up to 1 t
...
1111: digital filter enabled and filtering capability up to15 t
This filter can only be programmed when the I2C is disabled (PE = 0).
implementation.
Section 28.3: I2C
I2CCLK
DocID025202 Rev 7
implementation.
I2CCLK
I2CCLK
RM0365