Module regs
- Cr1
- Control register 1
- Cr2
- Control register 2
- Icr
- Interrupt clear register
- Isr
- Interrupt and Status register
- Oar1
- Own address register 1
- Oar2
- Own address register 2
- Pecr
- PEC register
- Rxdr
- Receive data register
- Timeoutr
- Timeout register
- Timingr
- Timing register
- Txdr
- Transmit data register