
TE
CH
tm
10.3 Special Function Register 
F8H 
F0H 
B 
E8H 
E0H 
ACC 
D8H 
D0H 
PSW 
C8H 
T2CON 
C0H 
B8H 
IP 
B0H 
P3 
A8H 
IE 
A0H 
P2 
98H 
SCON 
90H 
P1 
88H 
TCON 
80H 
P0* 
*Note: P0:Internal still keeping, but for pad dominate, no external pin assignment  
Accumulator : ACC 
ACC is the Accumulator register. The mnemonics for Accumulator-Specific instructions, however, refer to the 
Accumulator simply as A. 
B Register : B 
The B register is used during multiply and divide operations. For other instructions it can be treated as another scratch 
pad register. 
Program Status Word : PSW 
The PSW register contains program status information as detailed in 
CY 
AC 
F0 
RS1 
BIT SYMBOL FUNCTION 
PSW.7  CY  Carry flag. 
PSW.6  AC  Auxiliary Carry flag. (For BCD operations.) 
PSW.5  F0   Flag 0. (Available to the user for general purposes.) 
PSW.4  RS1  Register bank select control bit 1. 
Set/cleared by software to determine working register bank. (See 
Note.
) 
PSW.3  RS0  Register bank select control bit 0. 
Set/cleared by software to determine working register bank. (See 
Note.
) 
PSW.2  OV  Overflow flag. 
PSW.1  —   User-definable flag. 
PSW.0  P    Parity flag. 
Set/cleared by hardware each instruction cycle to indicate an odd/even number of “one” bits in the Accumulator, 
i.e., even parity. 
NOTE
: The contents of (RS1, RS0) enable the working register banks as follows: 
(0,0)— Bank 0 (00H–07H) 
(0,1)— Bank 1 (08H–0fH) 
(1,0)— Bank 2 (10H–17H) 
(1,1)— Bank 3 (18H–17H) 
                 T81L0006A/B
TM Technology Inc. reserves the right 
P. 7                
Publication Date: AUG. 2005 
to change products or specifications without notice.                                 Revsion : B
T2MOD RCAP2L RCAP2H 
SBUF 
TMOD 
TL0 
SP 
DPL 
TL2 
TH0 
TH2 
TH1 
TL1 
DPH 
WDREL 
PCON 
RS0 
OV 
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P