EM73P461A
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
PROGRAM COUNTER (4K/8K ROM)
Program counter ( PC ) is composed by a 12-bit counter for 4K ROM/13-bit counter for 8K ROM which indicates
the next executed address for the instruction of program ROM.
For a 4K - byte size ROM, PC can indicate address form 000h - FFFh, for BRANCH and CALL instrcutions,
PC is changed by instruction indicating.
For a 8K - byte size ROM, PC can indicate address form 0000h - 1FFFh, for BRANCH and CALL instrcutions,
PC is changed by instruction indicating.
(1) Branch instruction:
SBR a
Object code: 00aa aaaa
Condition: SF=1; PC ← PC 11-6.a ( branch condition satisified )
PC
SF=0; PC ← PC +1( branch condition not satisified )
PC Original PC value + 1
Hold original PC value+1 a
a
a
a
a
a
(for 4K/8K ROM)
LBR a
Object code: 1100 aaaa aaaa aaaa
Condition: SF=1; PC ← a ( branch condition satisified )
PC
SF=0 ; PC ← PC + 2 ( branch condition not satisified )
PC Original PC value + 2
a
a
a
a
a
a
a
a
a
a
a
a
(for 4K/8K ROM)
SLBR a
Object code: 0101 0101 1100 aaaa aaaa aaaa (a : 1000 ~ 1FFFh)
0101 0111 1100 aaaa aaaa aaaa (a : 0000 ~ 0FFFh)
Condition: SF=1; PC ← a ( branch condition satisified )
PC
a
a
a
a
a
a
a
a
a
a
a
a
(only for 8K ROM)
SF=0 ; PC ← PC + 2 ( branch condition not satisified )
PC
Original PC value + 2
* This specification are subject to be changed without notice.
12.27.2001
9
ELAN [ ELAN MICROELECTRONICS CORP ]
