M D T 1 0P509(A)
P509(A)
(3) PC (Program Counter) : R2
Write PC, CALL --- always 0
JUMP --- from instruction word
RTIW, RET --- from STACK
A9
A8
Write PC, JUMP, CALL --- from STATUS b5
RTIW, RET --- from STACK
A7~A0
Write PC --- from ALU
JUMP, CALL --- from instruction word
RTIW, RET --- from STACK
(4) STATUS (Status register) : R3
Bit
0
1
2
3
4
5
6
7
Symbol
C
HC
Z
PF
TF
PAGE
——
PCWUF
Carry bit
Half Carry bit
Zero bit
Power down bit
Function
WDT Timer overflow Flag bit
ROM page select bit
Unimplemented
Pin change wake up from sleep
(5) MSR (Memory Bank Select Register) : R4
b7
b6
b5
b4
b3
b2
b1
b0
Bank select
Read only “1”
Indirect Addressing Mode
P.3
2010/7 PA
MDTIC [ Micon Design Technology Corporation ]
