AT89S8253 Atmel Corporation, AT89S8253 Datasheet - Page 33

• Manufacturer Part Number: AT89S8253
• Manufacturer: Atmel Corporation

Specifications of AT89S8253

• Flash (kbytes): 12 Kbytes
• Max. Operating Frequency: 24 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 0.25
• Eeprom (bytes): 2048
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 3
• Isp: SPI
• Watchdog: Yes

16. Oscillator Characteristics
3286P–MICRO–3/10
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be
configured for use as an on-chip oscillator, as shown in
crystal or ceramic resonator may be used. For frequencies above 16MHz it is recommended that
C1 be replaced with R1 for improved startup performance. Note that the internal structure of the
devices adds about 10 pF of capacitance to both XTAL1 and XTAL2. The total capacitance on
XTAL1 or XTAL2, including the external load capacitor (C1/C2) plus internal device load, board
trace and crystal loadings, should not exceed 20 pF.
the relationship between clock loading and the respective resulting clock amplitudes.
Figure 16-1. Oscillator Connections
Note:
Figure 16-2. Quartz Crystal Clock Source (A)
C1, C2 = 0–10 pF for Crystals
R1
6
5
4
3
2
1
0
0
(A) Low Frequency
= 0–10 pF for Ceramic Resonators
= 4–5 MΩ
C2
C1
4
Quartz Crystal Clock Input
8
~10 pF
~10 pF
Frequency (MHz)
12
Figure
(B) High Frequency
16
Figure 16-1
C2
R1
16-2, 16-3,
20
(A) and (B). Either a quartz
C1=C2=0pF
C1=C2=5pF
C1=C2=10pF
16-4
AT89S8253
and
24
~10 pF
~10 pF
16-5
illustrate
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