Module regs
- Cr
 - Control register
 - Dinr
 - Data input register
 - Doutr
 - Data output register
 - Icr
 - Interrupt clear register
 - Ier
 - Interrupt enable register
 - Isr
 - Interrupt status register
 - Ivr
 - Initialization vector register
 - Keyr
 - Key register
 - Sr
 - Status register
 - Suspr
 - Suspend register