W79E648 Datasheet, PDF (11/80 Pages) Winbond – Fast 8051 Compatible microcontroller with a redesigned Processor

Preliminary W79E648
A brief description of the SFRs now follows.
Port 0
Bit:
7
6
5
4
3
2
1
0
P0.7 P0.6 P0.5 P0.4 P0.3 P0.2 P0.1 P0.0
Mnemonic: P0
Address: 80h
Port 0 is an open-drain bi-directional I/O port. This port also provides a multiplexed low order
address/data bus during accesses to external memory.
Stack Pointer
Bit:
7
SP.7
6
SP.6
5
SP.5
4
SP.4
3
SP.3
2
SP.2
1
SP.1
0
SP.0
Mnemonic: SP
Address: 81h
The Stack Pointer stores the Scratchpad RAM address where the stack begins. In other words, it
always points to the top of the stack.
Data Pointer Low
Bit:
7
6
5
4
3
2
1
0
DPL.7 DPL.6 DPL.5 DPL.4 DPL.3 DPL.2 DPL.1 DPL.0
Mnemonic: DPL
This is the low byte of the standard 8052 16-bit data pointer.
Address: 82h
Data Pointer High
Bit:
7
DPH.7
Mnemonic: DPH
6
DPH.6
5
DPH.5
4
DPH.4
3
2
1
DPH.3 DPH.2 DPH.1
Address: 83h
0
DPH.0
This is the high byte of the standard 8052 16-bit data pointer.
Power Control
Bit:
7
6
5
SM0D SMOD0
-
4
3
2
1
0
-
GF1 GF0
PD
IDL
Mnemonic: PCON
Address: 87h
SMOD : This bit doubles the serial port baud rate in mode 1, 2, and 3 when set to 1.
SMOD0: Framing Error Detection Enable: When SMOD0 is set to 1, then SCON.7 indicates a Frame
Error and acts as the FE flag. When SMOD0 is 0, then SCON.7 acts as per the standard
8052 function.
GF1-0: These two bits are general purpose user flags.
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Publication Release Date: 05/31/2004
Revision A1