EM73PA88A
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
PROGRAM COUNTER (16K ROM)
Program counter ( PC ) is composed by a 13-bit counter, which indicates the next executed address for the
instruction of program ROM instruction.
For BRANCH and CALL instructions, PC is changed by instruction indicating. PC only can indicate the address
from 0000h-1FFFh. The bank number is decided by P3.
(1) Branch instruction:
SBR a
Object code: 00aa aaaa
Condition: SF=1; PC ← PC 12-6.a ( branch condition satisified )
PC Hold original PC value+1
SF=0; PC← PC +1( branch condition not satisified)
PC Original PC value + 1
a
a
a
a
a
a
LBR a
Object code: 1100 aaaa aaaa aaaa
Condition: SF=1; PC ← PC 12.a ( branch condition satisified )
Hold
+2
PC
a
a a
a
a
a
a
a
a
a
a
a
SF=0; PC← PC +2( branch condition not satisified)
PC Original PC value + 2
SLBR a
Object code: 0101 0101 1100 aaaa aaaa aaaa (a:1000h~1FFFh)
0101 0111 1100 aaaa aaaa aaaa (a:0000h~0FFFh)
Condition: SF=1; PC ← a ( branch condition satisified)
PC a
SF=0 ; PC ← PC + 3 ( branch condition not satisified )
PC Original PC value + 3
a
a
a
a
a
a
a
a
a
a
a
a
(2) Subroutine instruction:
SCALL a
Object code: 1110 nnnn
Condition : PC ← a ; a=8n+6 ; n=1..Fh ; a=86h, n=0
PC 0
LCALL a
0
0
0
0
a
a
a
a
a
a
a
a
Object code: 0100 0aaa aaaa aaaa
Condition: PC ← a
* This specification are subject to be changed without notice.
10.8.2001
11
ELAN [ ELAN MICROELECTRONICS CORP ]
