em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 167

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 05.05.2010
(This specification is subject to change without further notice)
Bit 8 ~ Bit 7 (CLKS1 ~ CLKS0): Instruction period option bit
Bit 6 (ENWDTB): Watchdog Timer Enable bit
Bit 5 ~ Bit 3 (OSC2 ~ OSC0): Oscillator Mode selection bits
Bit 2 ~ Bit 0 (Protect): Protect select bit as shown below:
Refer to the Instruction Set in Section 6.20 below.
0: Disable (default)
1: Enable
Oscillator Modes as defined by OSC2 ~ OSC0:
1
2
3
4
XT
HXT
LXT1
LXT2
IRC (Internal RC oscillator mode);
P55, P54 act as I/O pin
IRC (Internal RC oscillator mode);
P55 act as I/O pin
P54 act as RCOUT pin
ERC (External RC oscillator mode);
P55 act as ERCin pin
P54 act as I/O pin
ERC (External RC oscillator mode);
P55 act as ERCin pin
P54 act as RCOUT pin with Open-Drain
Frequency range of XT mode is 6 MHz ~ 1 MHz.
Frequency range of HXT mode is 16 MHz ~ 6 MHz.
Frequency range of LXT1 mode is 1 MHz ~ 100kHz.
Frequency range of LXT2 mode is 32kHz.
Instruction Period
4 clocks (default)
2 clocks
8 clocks
16 clocks
Protect
1
(Crystal oscillator mode) (default)
2
3
4
(High Crystal oscillator mode)
1
0
(Low Crystal 1 oscillator mode)
(Low Crystal 2 oscillator mode)
ELAN UICE only supports the 2 or 4 clocks instruction period.
EM78F648/644/642/641/548/544/542/541N
Mode
Protect
Disable
CLKS1
Enable
0
0
1
1
NOTE
CLKS0
0
1
0
1
OSC2
0
0
0
0
1
1
1
1
8-Bit Microcontroller
OSC1
0
0
1
1
0
0
1
1
OSC0
1
0
1
0
1
0
1
0
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