Control A

Name:
CTRLA
Offset:
0x00
Reset:
0x00
Access:
-
Bit76543210
SDASETUPSDAHOLD[1:0]FMPEN
AccessR/WR/WR/WR/W
Reset0000

Bit 4 – SDASETUP: SDA Setup Time

SDA Setup Time

This bit is used in TWI Client mode to select the clock hold time to ensure minimum setup time on the SDA out signal.

By default, there are four clock cycles of setup time on the SDA out signal while reading from the client part of the TWI module. Writing this bit to ‘1’ will change the setup time to eight clock cycles.

ValueNameDescription
0 4CYC SDA setup time is four clock cycles
1 8CYC SDA setup time is eight clock cycles

Bits 3:2 – SDAHOLD[1:0]: SDA Hold Time

SDA Hold Time

Writing this bit field selects the SDA hold time for the TWI. See the Electrical Characteristics section for details.

ValueNameDescription
0x0 OFF Hold time OFF
0x1 50NS Short hold time
0x2 300NS Meets the SMBus 2.0 specifications under typical conditions
0x3 500NS Meets the SMBus 2.0 specifications across all corners

Bit 1 – FMPEN: FM Plus Enable

FM Plus Enable

Writing a ‘1’ to this bit selects the 1 MHz bus speed (Fast mode plus, Fm+) for the TWI in default configuration or TWI Host in Dual mode configuration.

ValueDescription
0 Operating in Standard mode or Fast mode
1 Operating in Fast mode plus