
14
4188E–8051–08/06
AT/TS8xC51Rx2
Reset Value = XXXX XXX0b
Not bit addressable
For further details on the X2 feature, please refer to ANM072 available on the web
(http://www.atmel.com)
4
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
1
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
0
X2
CPU and peripheral clock bit
Clear to select 12 clock periods per machine cycle (STD mode, F
OSC
=F
XTAL
/
2).
Set to select 6 clock periods per machine cycle (X2 mode, F
OSC
=F
XTAL
).
Bit Number
Bit
Mnemonic
Description