W921E400A Datasheet, PDF (12/53 Pages) Winbond – 4-BIT MICROCONTROLLER

W921E400A/W921C400
0F8H
0F9H
0FAH
0FBH
0FCH
0FDH
0FEH
0FFH
Z
PC11
PC7
PC3
Z
PC11
PC7
PC3
C
PC10
PC6
PC2
C
PC10
PC6
PC2
PC9
PC5
PC1
PC9
PC5
PC1
PC12
PC8
PC4
PC0
PC12
PC8
PC4
PC0
Stack 1
Stack 0
6.2.3 Working Register Area
The located area from 040H to 04FH is known as working register. The instruction MOV WRn, A or
MOV A, WRn can move the A accumulator data to the working register or move working register data
to the A accumulator directly within the 1 word/1 machine cycle. The other direct instructions such as
MOV Mx, A or MOV A, Mx instruction are 2 words/2 machine cycles. Therefore the working register
can save the program memory size in ROM and improve the control speed in µC application circuit.
Only the WR0 to WR7 are available in the arithmetic and logic operation (i.e. only 040H to 047H can
be active). The instructions are as follows:
ADD A,
ADC A,
SUB A,
SBC A,
ANL A,
ORL A,
XRL A,
CMP A,
where x = 0 to 7.
WRx
WRx
WRx
WRx
WRx
WRx
WRx
WRx
6.3 Internal Oscillator Circuit
TM0
f TM0
MUX0
TM2
f_TM2
MUX2
TM3
f_TM3
MUX3
OSCI
OSCO
Crystal Type or
RC Type
f OSC
System Clock
(1/4)
f SYS
11-bit
Prescaler
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