W921E840A Datasheet, PDF (12/58 Pages) Winbond – 4-BIT MICROCONTROLLER

W921E840A/W921C840
6.2 RAM Memory Map
000H
Speical Control Registers
03FH
040H
Working Registers
04FH
050H
Serial Buffer Registers
07FH
080H
Stack Registers or
General Registers
0FFH
100H
Serial Buffer Registers or
General Registers
17FH
180H
General Registers
1FFH
000
063
064
079
080 _Stack
Registers
127
128 _{(040H to}
0FFH)
Serial
Buffer
Registers
General
(050H to Registers
255
14EH)
256
(040H to
1FFH)
383
384
511
(512 x 4-bit)
6.2.1 Special Control Register Area
There are 64 × 4-bit registers in the special control register area. All control registers such as DTMF
control register, serial speed control register, ..., etc. are in this area. Please refer to the following
table for detailed register map.
ADDR.
000H
001H
002H
003H
004H
005H
006H
007H
008H
009H
DESCRIPTION
Reserved or System Clock Control Register
Reserved
Reserved
Port P4 Pull High Resistor Register
Port P4 Output Type Register
Port P6 Pull High Resistor Register
Port P6 Output Type Register
Port PABCD Pull High Resistor Register
Port PABCD Output Type Register
Serial LSB Nibble Register
ABBREVIATION
(SYSCCR)
-
-
(P4PH)
(P4TP)
(P6PH)
(P6TP)
(PABCDPH)
(PABCDTP)
(SRLNR)
INITIAL VALUE
00H
-
-
00H
00H
00H
00H
00H
00H
02H
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