z86l88 ZiLOG Semiconductor, z86l88 Datasheet - Page 64

• Manufacturer Part Number: z86l88
• Description: Low-voltage Ir Microcontroller
• Manufacturer: ZiLOG Semiconductor

PS024102-0804
Power-On Reset (POR)
For 32-kHz crystal operation, an external feedback resistor (Rf) and a serial resis-
tor (Rd) are required. See Figure 44.
Figure 44. Oscillator Configuration
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).
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
tor circuit to stabilize before instruction execution begins.
The POR timer circuit is a one-shot timer triggered by one of three conditions:
•
•
•
C1
C2
C1
32 kHz XTAL
C1 = 20 pF, C = 33 pF
Rd = 56–470K
Rf = 10M
C2
Ceramic Resonator or Crystal
C1, C2 = 47pF TYP*
f = 8 MHz
Power Fail to Power OK status including Waking up from V
Stop-Mode Recovery (if D5 of SMR = 1)
WDT Time-Out
Rd
Rf
XTAL2
XTAL1
XTAL2
XTAL1
C2
C1
LC
C1, C2 = 22 pF
L = 130 µH*
f = 3 MHz*
L
XTAL2
XTAL1
External Clock
Low-Voltage IR Microcontroller
XTAL2
XTAL1
C1
RC
@ 3V VCC (TYP)
C1 = 33 pF*
R = 1K*
CC
BO
and the oscilla-
Standby
R
XTAL2
XTAL1
Z86L88
57