Datasheet

4341H–MP3–10/07

AT8xC51SND2C/MP3B

8. Special Function Registers

The Special Function Registers (SFRs) of the AT8xC51SND2C derivatives fall into the catego-

ries detailed in Table 8-1 to Table . The relative addresses of these SFRs are provided together

with their reset values in Table 8-19. In this table, the bit-addressable registers are identified by

Note 1.

Note: 1. ENBOOT bit is only available in AT89C51SND2C product.

Table 8-1. C51 Core SFRs

Mnemonic Add Name 7 6 5 4 3 2 1 0

ACC E0h Accumulator

B F0h B Register

PSW D0h Program Status Word CY AC F0 RS1 RS0 OV F1 P

SP 81h Stack Pointer

DPL 82h Data Pointer Low Byte

DPH 83h Data Pointer High Byte

Table 8-2. System Management SFRs

Mnemonic Add Name 7 6 5 4 3 2 1 0

PCON 87h Power Control SMOD1 SMOD0 - - GF1 GF0 PD IDL

AUXR 8Eh Auxiliary Register 0 - EXT16 M0 DPHDIS XRS1 XRS0 EXTRAM AO

AUXR1 A2h Auxiliary Register 1 - -

ENBOOT

(

- GF3 0 - DPS

NVERS FBh Version Number NV7 NV6 NV5 NV4 NV3 NV2 NV1 NV0

Table 8-3. PLL and System Clock SFRs

Mnemonic Add Name 7 6 5 4 3 2 1 0

CKCON 8Fh Clock Control - - - - - - - X2

PLLCON E9h PLL Control R1 R0 - - PLLRES - PLLEN PLOCK

PLLNDIV EEh PLL N Divider - N6 N5 N4 N3 N2 N1 N0

PLLRDIV EFh PLL R Divider R9 R8 R7 R6 R5 R4 R3 R2

Table 8-4. Interrupt SFRs

Mnemonic Add Name 7 6 5 4 3 2 1 0

IEN0 A8h Interrupt Enable Control 0 EA EAUD EMP3 ES ET1 EX1 ET0 EX0

IEN1 B1h Interrupt Enable Control 1 - EUSB - EKB - ESPI EI2C EMMC

IPH0 B7h Interrupt Priority Control High 0 - IPHAUD IPHMP3 IPHS IPHT1 IPHX1 IPHT0 IPHX0

IPL0 B8h Interrupt Priority Control Low 0 - IPLAUD IPLMP3 IPLS IPLT1 IPLX1 IPLT0 IPLX0

IPH1 B3h Interrupt Priority Control High 1 - IPHUSB - IPHKB IPHADC IPHSPI IPHI2C IPHMMC