AT89C51ID2-SMSIM ATMEL [ATMEL Corporation], AT89C51ID2-SMSIM Datasheet - Page 62

• Manufacturer Part Number: AT89C51ID2-SMSIM
• Description: 8-bit Flash Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

62
AT89C51ID2
Table 45. PCON Register
PCON - Power Control Register (87h)
Reset Value = 00X1 0000b
Not bit addressable
Power-off flag reset value will be 1 only after a power on (cold reset). A warm reset
doesn’t affect the value of this bit.
Number
SMOD1
Bit
7
7
6
5
4
3
2
1
0
Mnemonic
SMOD0
SMOD1
SMOD0
POF
GF1
GF0
Bit
6
IDL
PD
-
Serial port Mode bit 1 for UART
Set to select double baud rate in mode 1, 2 or 3.
Serial port Mode bit 0 for UART
Cleared to select SM0 bit in SCON register.
Set to select FE bit in SCON register.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Power-Off Flag
Cleared to recognize next reset type.
Set by hardware when VCC rises from 0 to its nominal voltage. Can also be set
by software.
General purpose Flag
Cleared by user for general purpose usage.
Set by user for general purpose usage.
General purpose Flag
Cleared by user for general purpose usage.
Set by user for general purpose usage.
Power-Down mode bit
Cleared by hardware when reset occurs.
Set to enter power-down mode.
Idle mode bit
Cleared by hardware when interrupt or reset occurs.
Set to enter idle mode.
5
-
POF
4
GF1
3
Description
GF0
2
PD
1
4289A–8051–09/03
IDL
0