27.5.1 Control A
| Name: | CTRLA |
| Offset: | 0x00 |
| Reset: | 0x00 |
| Property: | - |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| INPUTLVL | SDASETUP | SDAHOLD[1:0] | FMPEN | ||||||
| Access | R/W | R/W | R/W | R/W | R/W | ||||
| Reset | 0 | 0 | 0 | 0 | 0 | ||||
Bit 6 – INPUTLVL Input Voltage Transition Level
| Value | Name | Description |
|---|---|---|
| 0 | I2C | I2C input voltage transition level |
| 1 | SMBUS | SMBus 3.0 input voltage transition level |
Bit 4 – SDASETUP SDA Setup Time
This bit is used in TWI Client mode to select the clock hold time and to ensure the minimum setup time on the SDA out signal.
| Value | Name | Description |
|---|---|---|
| 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
This bit field selects the SDA hold time for the TWI. See the Electrical Characteristics section for details.
| Value | Name | Description |
|---|---|---|
| 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 across all corners |
Bit 1 – FMPEN FM Plus Enable
Writing a ‘1’ to this bit selects the 1 MHz bus speed for the
TWI in default configuration or the TWI
host in Dual mode configuration.
| Value | Name | Description |
|---|---|---|
| 0 | OFF | Operating in Standard mode or Fast mode |
| 1 | ON | Operating in Fast mode Plus |