EM78159NAS EMC [ELAN Microelectronics Corp], EM78159NAS Datasheet - Page 31

• Manufacturer Part Number: EM78159NAS
• Description: 8-Bit Microcontroller with OTP ROM
• Manufacturer: EMC [ELAN Microelectronics Corp]

Product Specification (V1.0) 03.10.2006
(This specification is subject to change without further notice)
4.7.2 Crystal Oscillator/Ceramic Resonators (XTAL)
EM78P159N can be driven by an external clock signal through the OSCI pin as shown
in the following figure.
In the most applications, Pin OSCI and Pin OSCO can be connected with a crystal or
ceramic resonator to generate oscillation. Figure below depicts such circuit. The same
thing applies whether it is in the HXT mode or in the LXT mode. The following table
provides the recommended values of C1 and C2. Since each resonator has its own
attribute, you should refer to its specification for appropriate values of C1 and C2. RS,
a serial resistor, may be necessary for AT strip cut crystal or low frequency mode.
Ceramic Resonators
Crystal Oscillator
Oscillator Type
Capacitor Selection Guide for Crystal Oscillator or Ceramic Resonator
EM78P159N
EM78P159N
Figure 4-8a External Clock Input Circuit
OSCO
Figure 4-8b Crystal/Resonator Circuit
Frequency Mode
OSCO
OSCI
OSCI
HXT
HXT
LXT
XTAL
RS
Frequency
32.768kHz
455 kHz
2.0 MHz
4.0 MHz
100KHz
200KHz
455KHz
1.0MHz
2.0MHz
4.0MHz
C1
C2
8-Bit Microcontroller with OTP ROM
Ext. Clock
100~150
C1(pF)
20~40
10~30
20~40
15~30
25
15
15
25
25
EM78P159N
100~150
20~150
C2(pF)
20~40
10~30
15~30
15
25
25
15
15
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