MC81F4332 Datasheet, PDF (47/198 Pages) Finechips – ABOV SEMICONDUCTOR 8-BIT SINGLE-CHIP MICROCONTROLLERS

MC81F4432
8. ROM OPTION
The ROM Option is a start-condition byte of the chip. The default ROM Option value is 00H (LVR
enable and External RC is selected). It can be changed by appropriate writing tools such as
PGMPlusUSB, ISP, etc.
8.1 Rom Option
7
6
5
4
ROM
LVREN
LVRS
–
OPTION
LVREN LVR Enable/Disable bit
LVRS LVR Level Selection bits
–
bit4 – bit3
OSCS Oscillator Selection bits
3
2
1
0
–
OSCS
0: Enable (R35)
1: Disable (RESETB)
00: 2.4V
01: 2.7V
10: 3.0V
11: 4.0V
Not used in MC81F4x32
000: External RC
001: Internal RC; 4MHz
010: Internal RC; 2MHz
011: Internal RC; 1MHz
100: Internal RC; 8MHz
101: Not available ( Note 4 )
110: Not available ( Note 5 )
111: Crystal/ceramic oscillator
Note :
1. When LVR is enabled, LVR level should be set to appropriate value, not default value.
2. When you select the Crystal/ceramic oscillator, R33 and R34 pins are automatically
selected for XIN and XOUT mode.
3. When you select the external RC, R34 pin is automatically selected for XIN mode.
4. If OSCS is set by „101‟, Oscillator works as „Internal RC; 4MHz‟ mode.
5. If OSCS is set by „110‟, Oscillator works as „Internal RC; 2MHz‟ mode.
October 19, 2009 Ver.1.35
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