Z8F042AHJ020SC00TR Zilog, Z8F042AHJ020SC00TR Datasheet - Page 199

• Manufacturer Part Number: Z8F042AHJ020SC00TR
• Description: IC ENCORE XP MCU FLASH 4K 28SSOP
• Manufacturer: Zilog
• Series: Encore!® XP®r

Specifications of Z8F042AHJ020SC00TR

• Core Processor: Z8
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: IrDA, UART/USART
• Peripherals: Brown-out Detect/Reset, LED, LVD, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 23
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: Z8F042AHJ020SC00T

Table 108. Oscillator Configuration and Selection
PS022825-0908
Clock Source
Internal Precision
RC Oscillator
External Crystal/
Resonator
External RC
Oscillator
External Clock
Drive
Internal Watchdog
Timer Oscillator
Caution:
OSC Control Register Unlocking/Locking
To write the oscillator control register, unlock it by making two writes to the OSCCTL
register with the values
changes the value of the actual register and returns the register to a locked state. Any other
sequence of oscillator control register writes has no effect. The values written to unlock
the register must be ordered correctly, but are not necessarily consecutive. It is possible to
write to or read from other registers within the unlocking/locking operation.
Unintentional accesses to the oscillator control register can actually stop the chip by
switching to a non-functioning oscillator. To prevent this condition, the oscillator con-
trol block employs a register unlocking/locking scheme.
Characteristics
• 32.8 kHz or 5.53 MHz
• High accuracy
• No external components required
• 32 kHz to 20 MHz
• Very high accuracy (dependent on
• Requires external components
• 32 kHz to 4 MHz
• Accuracy dependent on external
• 0 to 20 MHz
• Accuracy dependent on external clock
• 10 kHz nominal
• Low accuracy; no external components
• Very low power consumption
crystal or resonator used)
components
source
required
E7H
followed by
18H
. A third write to the OSCCTL register
Required Setup
• Unlock and write Oscillator Control
• Configure Flash option bits for correct
• Unlock and write OSCCTL to enable
• Configure Flash option bits for correct
• Unlock and write OSCCTL to enable
• Write GPIO registers to configure PB3
• Unlock and write OSCCTL to select
• Apply external clock signal to GPIO
• Enable WDT if not enabled and wait
• Unlock and write Oscillator Control
Register (OSCCTL) to enable and
select oscillator at either 5.53 MHz or
32.8 kHz
external oscillator mode
crystal oscillator, wait for it to stabilize
and select as system clock (if the
XTLDIS option bit has been de-
asserted, no waiting is required)
external oscillator mode
crystal oscillator and select as system
clock
pin for external clock function
external system clock
until WDT Oscillator is operating.
Register (OSCCTL) to enable and
select oscillator
Z8 Encore! XP
Product Specification
®
F082A Series
Oscillator Control
188