EM78451AP EMC [ELAN Microelectronics Corp], EM78451AP Datasheet - Page 44

• Manufacturer Part Number: EM78451AP
• Description: 8-Bit Microcontroller
• Manufacturer: EMC [ELAN Microelectronics Corp]

EM78451
8-Bit Microcontroller
40 •
Table 10 Capacitor Selection Guide for Crystal Oscillator Ceramic Resonators
EM 78451
4.9.3 RC Oscillator Mode
For some applications that do not need a very precise timing calculation, the RC
oscillator (Fig. 22 & Fig. 23) offers cost-effective savings. Nevertheless, it should be
noted that the frequency of the RC oscillator is influenced by the supply voltage, the
values of the resistor (Rext), the capacitor (Cext), and even by the operation
temperature. Moreover, the frequency also changes slightly from one chip to another
due to the manufacturing process variation.
Crystal Oscillator
Oscillator Type Frequency Mode
EM 78451
Resonator
Ceramic
OSCI
OSCI
Fig. 21 Circuit for Crystal/Resonator-Parallel Mode
Fig. 20 Circuit for Crystal/Resonator-Series Mode
HXT
HXT
LXT
7404
7404
10K
C1
(This specification is subject to change without further notice)
32.768 KHz
Frequency
7404
455 KHz
100 KHz
200 KHz
455 KHz
XTAL
1.0 MHz
2.0 MHz
4.0 MHz
1.0 MHz
2.0 MHz
4.0 MHz
7404
330
4.7K
C2
Product Specification (V1.2) 05.27.2004
XTAL
C
10K
C1 (pF)
10~150
40~80
20~40
10~30
20~40
15~30
25
25
25
15
15
7404
330
VDD
C2 (pF)
10~150
20~150
40~80
20~40
10~30
15~30
15
25
25
15
15