DS80C320-ECD DALLAS [Dallas Semiconductor], DS80C320-ECD Datasheet - Page 19

• Manufacturer Part Number: DS80C320-ECD
• Description: High-Speed Microcontroller User Guide
• Manufacturer: DALLAS [Dallas Semiconductor]

SPECIAL FUNCTION REGISTERS
Most of the unique features of the High-Speed Microcontroller family are controlled by bits in special
function registers (SFRs) located in unused locations in the 8051 SFR map. This allows for increased
functionality while maintaining complete instruction set compatibility.
The description for each bit indicates its read and write access, as well as its state after a power on reset.
Bits which are affected by a no-battery reset are also indicated. Note that many bits and registers are
unique to specific devices, and their functions will vary between different members of the High-Speed
Microcontroller family.
Port 0 (P0)
Stack Pointer (SP)
Data Pointer Low 0 (DPL)
RTCD1
SFR 80h
SFR 81h
SP.7-0
Bits 7-0
SFR 82h
DPL.7-0
Bits 7-0
P0.7-0
R=Unrestricted Read, W=Unrestricted Write, -n=Value after Reset
R=Unrestricted Read, W=Unrestricted Write, -n=Value after Reset
R=Unrestricted Read, W=Unrestricted Write, -n=Value after Reset
PDL.7
RW-1
RW-0
RW-0
SPECIAL
SP.7
P0.7
7
7
7
Port 0. This port functions as a multiplexed address/data bus during external
memory access, and as a general purpose I/O port on devices which incorporate
internal program memory. During external memory cycles, this port will contain
the LSB of the address when ALE is high, and data when ALE is low.
Stack Pointer. This stack pointer identifies the location where the stack will
begin. The stack pointer is incremented before every PUSH operation. This
register defaults to 07h after reset.
Data Pointer Low 0. This register is the low byte of the standard 80C32 16-bit
data pointer. DPL and DPH are used to point to non-scratchpad data RAM.
SPECIAL
PDL.6
RW-1
RW-0
RW-0
P0.6
SP.6
6
6
6
SPECIAL
PDL.5
RW-1
RW-0
RW-0
SP.5
P0.5
5
5
5
SPECIAL
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PDL.4
RW-1
RW-0
RW-0
SP.4
P0.4
4
4
4
SPECIAL
PDL.3
RW-1
RW-0
RW-0
SP.3
P0.3
3
3
3
SPECIAL
High-Speed Microcontroller User’s Guide
PDL.2
RW-1
RW-1
RW-0
P0.2
SP.2
SPECIAL
2
2
2
SPECIAL
PDL.1
RW-1
RW-1
RW-0
P0.1
SP.1
1
1
1
PDL.0
RW-1
RW-0
RW-1
P0.0
SP.0
FFh
0
0
0