Rainbow Electronics ATAR862-3 - Manual (Page 27)

27
ATAR862-3
4556B–4BMCU–02/03
Figure 24. RC-oscillator 2
4-MHz Oscillator The microcontroller block 4-MHz oscillator options need a crystal or ceramic resonator
connected to the OSC1 and OSC2 pins to establish oscillation. All the necessary oscilla-
tor circuitry is integrated, except the actual crystal, resonator, C3 and C4.
Figure 25. 4-MHz Crystal Oscillator
Figure 26. Ceramic Resonator
32-kHz Oscillator Some applications require long-term time keeping or low resolution timing. In this case,
an on-chip, low power 32-kHz crystal oscillator can be used to generate both the
SUBCL and the SYSCL. In this mode, power consumption is greatly reduced. The
32-kHz crystal oscillator can not be stopped while the power-down mode is in operation.
RC
oscillator 2
RcOut2
Stop
RcOut2
Osc-Stop
R
Trim
OSC1
OSC2
R
ext
V
DD
4-MHz
oscillator
4Out
4Out
OSC1
OSC2
*
Oscin
C1
*
C2
Oscout
XTAL
4 MHz
*
mask option
Stop
Osc-Stop
4-MHz
oscillator
4Out
Stop
4Out
Osc-Stop
OSC1
OSC2
*
Oscin
C1
*
C2
Oscout
Cer.
Res
*
mask option
C3
C4