C161U Datasheet, PDF (52/469 Pages) Infineon Technologies AG – Embedded C166 with USB, USART and SSC

C161U
Memory Organization
;----
;-------------------
;The scope of the EXTR #4 instruction...
;...ends here!
MOV
T8REL, R1
;T8REL uses 16-bit mem address,
;R1 is accessed via the SFR space
In order to minimize the use of the EXTR instructions the ESFR area mostly holds
registers which are mainly required for initialization and mode selection. Registers that
need to be accessed frequently are allocated to the standard SFR area, wherever
possible.
Note: The tools are equipped to monitor accesses to the ESFR area and will
automatically insert EXTR instructions, or issue a warning in case of missing or
excessive EXTR instructions.
4.2
External Memory Space
C161U is capable of using an address space of up to 2 MByte. Only parts of this address
space are occupied by internal memory areas. All addresses which are not used for on-
chip memory (RAM) or for registers may reference external memory locations. This
external memory is accessed via the C161U’s external bus interface.
Four memory bank sizes are supported:
– Non-segmented mode: 64 KByte
– 2-bit segmented mode: 256 KByte
– 4-bit segmented mode: 1 MByte
– 8-bit segmented mode: 2 MByte
with A15...A0 on PORT0 or PORT1
with A17...A16 on Port 4 and A15...A0 on
PORT0 or PORT1
with A19...A16 on Port 4 and A15...A0 on
PORT0 or PORT1
with A20...A16 on Port 4 and A15...A0 on
PORT0 or PORT1
Each bank can be directly addressed via the address bus, while the programmable chip
select signals can be used to select various memory banks.
C161U also supports four different bus types:
– Multiplexed 16-bit Bus
– Multiplexed 8-bit Bus
– Demultiplexed 16-bit Bus
– Demultiplexed 8-bit Bus
with address and data on PORT0 (Default after Reset)
with address and data on PORT0/P0L
with address on PORT1 and data on PORT0
with address on PORT1 and data on P0L
Memory model and bus mode are selected during reset by pin EA and PORT0 pins. For
further details about the external bus configuration and control please refer to chapter
"The External Bus Interface".
External word and byte data can only be accessed via indirect or long 16-bit addressing
modes using one of the four DPP registers. There is no short addressing mode for
external operands. Any word data access is made to an even byte address.
Data Sheet
52
2001-04-19