Address
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Access | |||||||||
| Reset |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| LEN[7:0] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| TENBITEN | HS | LENEN | ADDR[10:8] | ||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | |||
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | |||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| ADDR[7:0] | |||||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
Transaction Length
These bits define the transaction length of a DMA transaction from 0 to 255 bytes. The Transfer Length Enable (LENEN) bit must be written to '1' in order to use DMA.
Ten Bit Addressing Enable
This bit enables 10-bit addressing. This bit can be written simultaneously with ADDR to indicate a 10-bit or 7-bit address transmission.
| Value | Description |
|---|---|
| 0 | 10-bit addressing disabled. |
| 1 | 10-bit addressing enabled. |
High Speed
This bit enables High-speed mode for the current transfer from repeated START to STOP. This bit can be written simultaneously with ADDR for a high speed transfer.
| Value | Description |
|---|---|
| 0 | High-speed transfer disabled. |
| 1 | High-speed transfer enabled. |
Transfer Length Enable
| Value | Description |
|---|---|
| 0 | Automatic transfer length disabled. |
| 1 | Automatic transfer length enabled. |
Address
When ADDR is written, the consecutive operation will depend on the bus state:
UNKNOWN: INTFLAG.MB and STATUS.BUSERR are set, and the operation is terminated.
BUSY: The I2C host will await further operation until the bus becomes IDLE.
IDLE: The I2C host will issue a start condition followed by the address written in ADDR. If the address is acknowledged, SCL is forced and held low, and STATUS.CLKHOLD and INTFLAG.MB are set.
OWNER: A repeated start sequence will be performed. If the previous transaction was a read, the acknowledge action is sent before the repeated start bus condition is issued on the bus. Writing ADDR to issue a repeated start is performed while INTFLAG.MB or INTFLAG.SB is set.
STATUS.BUSERR, STATUS.ARBLOST, INTFLAG.MB and INTFLAG.SB will be cleared when ADDR is written.
The ADDR register can be read at any time without interfering with ongoing bus activity, as a read access does not trigger the host logic to perform any bus protocol related operations.
The I2C host control logic uses bit 0 of ADDR as the bus protocol’s read/write flag (R/W); 0 for write and 1 for read.