em78p131a ELAN Microelectronics Corp, em78p131a Datasheet - Page 30

• Manufacturer Part Number: em78p131a
• Description: 8-bit Microcontroller With Otp Rom
• Manufacturer: ELAN Microelectronics Corp

EM78P131A
8-Bit Microcontroller with OTP ROM
26 •
Table 7 RC Oscillator Frequencies
Note:
5.7.4 Internal RC Oscillator Mode
EM78P131A offers a versatile internal RC mode with default frequency value of 4MHz.
The Internal RC oscillator mode has other frequencies (1MHz, 8MHz, and 455kHz) that
can be set by Code Option (Word 1), RCM1, and RCM0. All these four main
frequencies can be calibrated by programming the Option Bits CAL0 ~ CAL2. The
table below describes the EM78P131A internal RC drift with variation of voltage,
temperature, and process.
1
2
3
:
:
:
100pF
300pF
20pF
Cext
Measured based on DIP packages.
The values are for design reference only.
The frequency drift is ± 30%.
E M 78P 131 A
Figure 5-13 External RC Oscillator Mode Circuit
O S C I
Rext
100k
100k
100k
3.3k
5.1k
3.3k
5.1k
3.3k
5.1k
10k
10k
10k
(This specification is subject to change without further notice)
Average Fosc
Product Specification (V1.2) 09.16.2009
3.92 MHz
2.67 MHz
5V, 25°C
1.4 MHz
1.4 MHz
20.9kHz
150kHz
940kHz
476kHz
595kHz
400kHz
200kHz
50kHz
R ext
C ext
V cc
Average Fosc
3.65 MHz
2.60 MHz
1.40 MHz
1.33 MHz
3V, 25°C
156 kHz
917kHz
480kHz
570kHz
384kHz
203kHz
52kHz
20kHz