Memory-Mapped Sfrs; Peripheral Sfrs - Intel 8XC196MC User Manual

4.1.5.1

Memory-mapped SFRs

Locations 1FE0–1FFFH contain memory-mapped SFRs (see Table 4-3). Locations in this range
that are omitted from the table are reserved. The memory-mapped SFRs must be accessed with
indirect or indexed addressing modes, and they cannot be windowed. If you read a location in this
range through a window, the SFR appears to contain FFH (all ones). If you write a location in
this range through a window, the write operation has no effect on the SFR.
The memory-mapped SFRs are accessed through the memory controller, so instructions that op-
erate on these SFRs execute as they would from external memory with zero wait states.
4.1.5.2

Peripheral SFRs

Locations 1F00–1FDFH provide access to the peripheral SFRs. Table 4-6 on page 4-8, Table 4-6
on page 4-8, and Table 4-6 on page 4-8 list the peripheral SFRs of the 8XC196MC, 8XC196MD,
and 8XC196MH, respectively. Locations that are omitted from the tables are reserved. The pe-
ripheral SFRs are I/O control registers; they are physically located in the on-chip peripherals.
These peripheral SFRs can be windowed and they can be addressed either as words or bytes, ex-
cept as noted in the tables.
The peripheral SFRs are accessed directly, without using the memory controller, so instructions
that operate on these SFRs execute as they would if they were operating on the register file.
Table 4-3. Memory-mapped SFRs
Ports 3, 4, 5, UPROM SFRs
Hex Address High (Odd) Byte
1FFE P4_PIN
1FFC P4_REG
• • • • • •
1FF6 P5_PIN
1FF4 P5_REG
1FF2 P5_DIR
1FF0 P5_MODE
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MEMORY PARTITIONS
Low (Even) Byte
P3_PIN
P3_REG
• • •
USFR
Reserved
Reserved
Reserved
4-5