TS87C51RD2_14 Datasheet, PDF (14/86 Pages) ATMEL Corporation – extra 8-bit I/O ports available on RD2 with high pin count packages

Bit
Bit Number Mnemonic Description
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.
CPU and peripheral clock bit
0
X2
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).
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)
14 AT/TS8xC51Rx2
4188F–8051–01/08