Datasheet

22
A/T89C51CC01
4129N–CAN–03/08
Registers Table 15. PCON Register
PCON (S:87h) – Power configuration Register
Reset Value = 00X1 0000b
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 V
cc
rises from 0 to its nominal voltage. Can also be set by
software.
3 GF1
General-purpose flag 1
One use is to indicate whether an interrupt occurred during normal operation or
during Idle mode.
2 GF0
General-purpose flag 0
One use is to indicate whether an interrupt occurred during normal operation or
during Idle mode.
1 PD
Power-down Mode bit
Cleared by hardware when an interrupt or reset occurs.
Set to activate the Power-down mode.
If IDL and PD are both set, PD takes precedence.
0 IDL
Idle Mode bit
Cleared by hardware when an interrupt or reset occurs.
Set to activate the Idle mode.
If IDL and PD are both set, PD takes precedence.