Control register 2
| SADD | Slave address bit (master mode) |
| RD_WRN | Transfer direction (master mode) |
| ADD10 | 10-bit addressing mode (master mode) |
| HEAD10R | 10-bit address header only read direction (master receiver mode) |
| START | Start generation |
| STOP | Stop generation (master mode) |
| NACK | NACK generation (slave mode) |
| NBYTES | Number of bytes |
| RELOAD | NBYTES reload mode |
| AUTOEND | Automatic end mode (master mode) |
| PECBYTE | Packet error checking byte |