Users Guide: DS80C390 Supplement Manual
High-Speed Microcontroller User’s Guide: DS80C390 Supplement 
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SPECIAL FUNCTION REGISTERS 
Most of the unique features of the high-speed microcontroller family are controlled by bits in special 
function registers (SFRs) located in unused locations in the 8051 SFR map. This allows for increased 
functionality while maintaining complete instruction set compatibility. The SFRs reside in register 
locations 80h-FFh and are accessed using direct addressing. SFRs that end in 0 or 8 are bit addressable. 
The first table indicates the names and locations of the SFRs used by the DS80C390 and individual bits in 
those registers. Bits protected by the timed-access function are shaded. The second table indicates the 
reset state of all SFR bits. Following these tables is a complete description of DS80C390 SFRs that are 
new to the 8051 architecture or have new or modified functionality. 
Table 4-1. SPECIAL FUNCTION REGISTER LOCATION  
REGISTER  BIT 7  BIT 6  BIT 5  BIT 4  BIT 3  BIT 2  BIT 1  BIT 0  ADDRESS
P4  A19/P4.7 A18/P4.6 A17/P4.5 A16/P4.4 
CE3 /P4.3 CE2 /P4.2 CE1 /P4.1  CE0 /P4.0
80h 
SP  81h 
DPL  82h 
DPH  83h 
DPL1  84h 
DPH1  85h 
DPS ID1  ID0  TSL  —  —  —  —  SEL 86h 
PCON SMOD_0 SMOD0  OFDF  OFDE  GF1  GF0  STOP  IDLE  87h 
TCON TF1 TR1 TF0 TR0 IE1  IT1  IE0  IT0 88h 
TMOD GATE 
C/
T  
M1 M0 GATE 
C/ T  
M1 M0 89h 
TL0  8Ah 
TL1  8Bh 
TH0  8Ch 
TH1  8Dh 
CKCON WD1 WD0 T2M T1M T0M MD2 MD1 MD0 8Eh 
P1  INT5/P1.7 INT4/P1.6 INT3/P1.5 INT2/P1.4 TXD1/P1.3 RXD1/P1.2 T2EX/P1.1  T2/P1.0  90h 
EXIF IE5 IE4 IE3 IE2 CKRY RGMD RGSL BGS 91h 
P4CNT — SBCAN  P4CNT.5  P4CNT.4  P4CNT.3  P4CNT.2  P4CNT.1  P4CNT.0  92h 
DPX  93h 
DPX1  95h 
C0RMS0  96h 
C0RMS1  97h 
SCON0 SM0/FE_0  SM1_0  SM2_0  REN_0  TB8_0  RB8_0  TI_0  RI_0  98h 
SBUF0  99h 
RID  9Ah 
ESP —  —  —  —  —  —  ESP.1 ESP.0 9Bh 
AP  9Ch 
ACON —  —  —  —  —  SA  AM1  AM0 9Dh 
C0TMA0  9Eh 
C0TMA1  9Fh 
P2  A15/P2.7 A14/P2.6 A13/P2.5 A12/P2.4 A11/P2.3 A10/P2.2  A9/P2.1  A8/P2.0  A0h 
P5 
PCE3 /P5.7  PCE2 /P5.6  PCE1 /P5.5 CE0P /P5.4
C1TX/P5.3 C1RX/P5.2 C0RX/P5.1 C0TX/P5.0 A1h 
P5CNT CAN1BA CAN0BA  SP1EC C1_I/O C0_I/O P5CNT.2  P5CNT.1  P5CNT.0 A2h 
C0C ERIE STIE  PDE  —  CRST AUTOB ERCS  SWINT  A3h 
C0S BUSOFF CECE  WKS  RXS TXS ER2 ER1 ER0 A4h 
C0IR  INTIN7 INTIN6 INTIN5 INTIN4 INTIN3 INTIN2 INTIN1 INTIN0  A5h 
C0TE  A6h 
C0RE  A7h 
IE  EA  ES1 ET2 ES0 ET1 EX1 ET0 EX0 A8h 










