Datasheet

A/T89C51CC01

4129N–CAN–03/08

Table 39. PCON Register

PCON (S:87h)

Power Control Register

Reset Value = 00X1 0000b

Not bit addressable

7 6 5 4 3 2 1 0

SMOD1 SMOD0 – POF GF1 GF0 PD IDL

Bit

Number

Bit

Mnemonic Description

7 SMOD1

Serial port Mode bit 1

Set to select double baud rate in mode 1, 2 or 3.

6 SMOD0

Serial port Mode bit 0

Clear to select SM0 bit in SCON register.

Set to select FE bit in SCON register.

5 -

Reserved

The value read from this bit is indeterminate. Do not set this bit.

4 POF

Power-Off Flag

Clear to recognize next reset type.

Set by hardware when VCC rises from 0 to its nominal voltage. Can also be set

by software.

3 GF1

General-purpose Flag

Cleared by user for general-purpose usage.

Set by user for general-purpose usage.

2 GF0

General-purpose Flag

Cleared by user for general-purpose usage.

Set by user for general-purpose usage.

1 PD

Power-Down mode bit

Cleared by hardware when reset occurs.

Set to enter power-down mode.

0 IDL

Idle mode bit

Clear by hardware when interrupt or reset occurs.

Set to enter idle mode.