W921E840A Datasheet, PDF (49/58 Pages) Winbond – 4-BIT MICROCONTROLLER

W921E840A/W921C840
ROM CODE
b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
decoder code
I3 to I0
b3 b2 b1 b0
B register
b3 b2 b1 b0
A register
ROM ADDRESS
(0 to 4K)
0
b12 b11 b10 b9 b8
b7 b6 b5 b4
b3 b2 b1 b0
ROM CODE b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Example:
X Y b3 b2 b1 b0 b3 b2 b1 b0
OP2
OP1
ROM Code Output to Register or Port
XY
OP2
0 0 Disable
0 1 B register
1 0 Port P2
1 1 Both
OP1
Disable
A register
Disable
A register
.
.
.
MOV A, #03H
MOV B, #01H
TBL 02H
.
.
.
ORG 213H
DC
3DCH
.
.
.
; A = 0CH, B = Port2 = 0DH
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Publication Release Date: July 1999
Revision A3