EM78P468LAQ EMC [ELAN Microelectronics Corp], EM78P468LAQ Datasheet - Page 40

• Manufacturer Part Number: EM78P468LAQ
• Description: 8-BIT Microcontroller
• Manufacturer: EMC [ELAN Microelectronics Corp]

EM78P468L
8-BIT Microcontroller
36 •
4.6 Oscillator
4.6.1
4.6.2
This LSI can operate in the three different oscillator modes from main oscillator (R-OSCI,
OSCO), such as RC oscillator with external resistor and Internal capacitor mode (ERIC);
crystal oscillator mode; and PLL operation mode (R-OSCI connected 0.01 μ F capacitor
to Ground). User can select one of them by programming FMMD1 and FMMD0 in the
CODE options register. The sub-oscillator can be operated in crystal mode and ERIC
mode. Table 3 below shows how these three modes are defined.
Table 3 Oscillator Modes as defined by FSMD, FMMD1, FMMD0.
Table 4 Summary of maximum operating speeds
When operate on PLL mode, the High frequency determined by sub-oscillator. We can
choose RD register to change high oscillator frequency. The relation between high
frequency (Fm) and sub-oscillator is shown as below table:
FSMD
0
0
0
1
1
1
Phase Lock Loop (PLL Mode)
Oscillator Modes
Conditions
Two clocks
FMMD1
0
0
1
0
0
1
EM78P468N
FMMD0
X
X
0
1
0
1
Circuit for PLL mode
R-OSCI
Xout
Xin
RC type (ERIC)
Crystal type
PLL type
RC type (ERIC)
Crystal type
PLL type
VDD
2.3
3.0
5.0
(This specification is subject to change without further notice)
XTAL
Main clock
Product Specification (V1.0) 03.15.2006
Fxt max.(MHz)
0.01uF
C1
C2
10
4
8
RC type (ERIC)
RC type (ERIC)
RC type (ERIC)
Crystal type
Crystal type
Crystal type
Sub-clock