P89V52X2 Datasheet, PDF (12/56 Pages) NXP Semiconductors – 8-bit 80C51 low power 8 kB flash microcontroller with 256 B RAM, 192 B data EEPROM

NXP Semiconductors
P89V52X2
80C51 with 256 B RAM, 192 B data EEPROM
C2
XTAL2
XTAL1
C1
V_SS
002aaa545
Fig 5. Oscillator characteristics (using the on-chip oscillator)
n.c.
XTAL2
external
oscillator
signal
XTAL1
V_SS
002aaa546
Fig 6. Oscillator characteristics (external clock drive)
6.3.2 Clock control register (CKCON)
By default, the device runs at twelve clocks per machine cycle. The device may be run in
6 clock per machine cycle mode by programming of either a non-volatile bit (FX2) or an
SFR bit (Table 5 “Clock modes”). If the FX2 non-volatile bit is programmed the device will
run in 6-clock mode and the X2 SFR bit has no effect. If the FX2 bit is erased, then the
clock mode is controlled by the X2 SFR bit.
Table 5. Clock modes
FX2 clock mode bit (UCFG.1) X2 bit (CLKCON.0)
erased
0
erased
1
programmed
x
CPU clock mode
12-clock mode (default)
6-clock mode
6-clock mode
6.4 ALE control
Table 6. AUXR - Auxiliary register (address 8EH) bit allocation
Not bit addressable; Reset value 00H
Bit
7
6
5
4
3
2
Symbol
-
-
-
-
-
-
1
0
-
AO
P89V52X2_1
Preliminary data sheet
Rev. 01 — 7 June 2007
© NXP B.V. 2007. All rights reserved.
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