Jameco Electronics Rabbit 3000 - Manual (Page 329)

320 Rabbit 3000 Microprocessor
The I/O banks on Port E (enabled for the User mode by IBUER) have a slightly different
operation in the User mode. Disabling user access to a given I/O bank not only causes
writes to the corresponding IBxCR register to be ignored in the User mode, but also inhib-
its the strobe associated with that I/O bank.
Access to the internal I/O registers listed in Table C-4 is always denied in the User mode.
Table C-4. I/O Addresses Inaccessible in User Mode
Register Name Mnemonic I/O Address
Global Control/Status Register GCSR 0x0000
Watchdog Timer Control Register WDTCR 0x0008
Watchdog Timer Test Register WDTTR 0x0009
Global Clock Modulator 0 Register GCM0R 0x000A
Global Clock Modulator 1 Register GCM1R 0x000B
Secondary Watchdog Timer Register
*
* These registers are only available on the Rabbit 3000A.
SWDTR 0x000C
Global Power Save Control Register GPSCR 0x000D
Global Output Control Register GOCR 0x000E
Global Clock Double Register GCDR 0x000F
MMU Instruction/Data Register MMIDR 0x0010
Stack Segment Register STACKSEG 0x0011
Data Segment Register DATASEG 0x0012
Segment Size Register SEGSIZE 0x0013
Memory Bank 0 Control Register MB0CR 0x0014
Memory Bank 1 Control Register MB1CR 0x0015
Memory Bank 2 Control Register MB2CR 0x0016
Memory Bank 3 Control Register MB3CR 0x0017
MMU Expanded Code Register MECR 0x0018
Memory Timing Control Register MTCR 0x0019
Breakpoint/Debug Control Register BDCR 0x001C
User Enable registers
* 0x03xx
Memory Protection registers
* 0x04xx