Datasheet

22
T89C51AC2
4127D–8051–02/03
Registers Table 14. PCON Register
PCON (S:87h) – Power configuration Register
Reset Value = 00X1 0000b
76543210
SMOD1 SMOD0 - POF GF1 GF0 PD IDL
Bit
Number
Bit
Mnemonic Description
7SMOD1
Serial port Mode bit 1
Set to select double baud rate in mode 1, 2 or 3
6SMOD0
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.
4POF
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.
3GF1
General-purpose flag 1
One use is to indicate whether an interrupt occurred during normal operation or
during Idle mode.
2GF0
General-purpose flag 0
One use is to indicate whether an interrupt occurred during normal operation or
during Idle mode.
1PD
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.
0IDL
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.