Z86L88 Datasheet, PDF (64/80 Pages) Zilog, Inc. – INFRARED REMOTE CONTROLLERS

Z86L88
Low-Voltage IR Microcontroller
57
For 32-kHz crystal operation, an external feedback resistor (Rf) and a serial resis-
tor (Rd) are required. See Figure 44.
XTAL1
C1
XTAL2
C2
XTAL1
C1
L
XTAL2
C2
XTAL1
C1
R
XTAL2
Ceramic Resonator or Crystal
C1, C2 = 47pF TYP*
f = 8 MHz
XTAL1
C1
Rf
LC
C1, C2 = 22 pF
L = 130 H*
f = 3 MHz*
RC
@ 3V VCC (TYP)
C1 = 33 pF*
R = 1K*
XTAL1
C2 Rd
XTAL2
32 kHz XTAL
C1 = 20 pF, C = 33 pF
Rd = 56–470K
Rf = 10M
Figure 44. Oscillator Configuration
XTAL2
External Clock
The crystal needs to be connected across XTAL1 and XTAL2 using the recom-
mended capacitors (capacitance greater than or equal to 22 pF) from each pin to
ground. The RC oscillator configuration is an external resistor connected from
XTAL1 to XTAL2, with a frequency-setting capacitor from XTAL1 to ground (see
Figure 44).
Power-On Reset (POR)
A timer circuit clocked by a dedicated on-board RC oscillator is used for the
Power-On Reset (POR) timer function. The POR time allows V_CC and the oscilla-
tor circuit to stabilize before instruction execution begins.
The POR timer circuit is a one-shot timer triggered by one of three conditions:
• Power Fail to Power OK status including Waking up from V_BO Standby
• Stop-Mode Recovery (if D5 of SMR = 1)
• WDT Time-Out
19-4614; Rev 0; 4/09