at90ls4433 ATMEL Corporation, at90ls4433 Datasheet - Page 6

• Manufacturer Part Number: at90ls4433
• Description: At90s4433 8-bit Avr Microcontroller With 4k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Clock Options
Crystal Oscillator
External Clock
6
AT90S/LS4433
XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier, which
can be configured for use as an On-chip Oscillator, as shown in Figure 2 and Figure 3.
Either a quartz crystal or a ceramic resonator may be used.
If the Oscillator is to be used as a clock for an external device, the clock signal from
XTAL2 may be routed to one HC buffer while reducing the load capacitor by 5 pF, as
shown in Figure 3. To drive the device from an external clock source, XTAL2 should be
left unconnected while XTAL1 is driven as shown in Figure 4.
Figure 2. Oscillator Connections
Figure 3. Using MCU Oscillator as a Clock for an External Device
Figure 4. External Clock Drive Configuration
REDUCE BY 5
P
F
MAX 1 HC BUFFER
XTAL1
XTAL2
1042H–AVR–04/03