Z86L7808PSC View Datasheet(PDF) - Zilog
Part Name
Description
MFG CO.
'Z86L7808PSC' PDF : 59 Pages View PDF
Z86L78
IR/Low-Voltage Microcontroller
Zilog
FUNCTIONAL DESCRIPTION (Continued)
Reset Functional Operation. Reset is internally driven
by four sources:
1. POR. (0 volts to operating voltage condition) usually
occurs upon powering up the MCU.
2. WDT. The WDT counts down and generates a reset,
usually to "wake" the part from a "sleep" condition.
3. Low Voltage Detection/Standby. An on-chip Voltage
Comparator checks that the VCC is at the required
level for correct operation of the device. Reset is
globally driven when VCC falls below VLV (Vrf1). A
small further drop in VCC causes the XTAL1 and
XTAL2 circuitry to stop the crystal or resonator clock.
Typical power consumption in this Low Voltage
Standby mode (ILV) is about 45 µA (varying with the
number of Masks selectable options enabled). When
the power level is returned to above VLV, the device
will perform a POR and function normally. If the VCC is
allowed to stay above 1.5V, the RAM content is
preserved. Low Voltage Standby was designed to
allow the device to draw power from board level
decoupling capacitors during battery changes.
4. Stop Mode Recovery (Partial reset).
Low Voltage Protection. An on-board Voltage Compara-
tor checks that VCC is at the required level to ensure cor-
rect operation of the device. Reset is globally driven if VCC
is below Vrf1.
Maximum (Vrf1) Conditions:
TA = 0°C, +70°C Internal clock frequency equal to or less
than 4.0 MHz
Note: The internal clock frequency is one-half the external
clock frequency.
The device functions normally at or above Vrf1 under all
conditions (Figure 39).
Mask Selectable Options. There are five Mask Select-
able Options to choose from based on ROM code require-
ments. These are:
RC/Other
Port 0 Pull-ups
Port 2 Pull-ups
Port 3 Pull-ups
32 kHz Option
Clock Source
On/Off
On/Off
On/Off
On/Off
Vrf1
T
B
D
0
15
25
35
45
55 70°C
Temperature
Figure 39. Z86L78 Low Voltage
vs Temperature at 8 MHz
2-48
DS97LVO0701
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