M16C65 Datasheet, PDF (147/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
8.2.8 40 MHz On-Chip Oscillator Control Register 0 (FRA0)
8. Clock Generator
40 MHz On-Chip Oscillator Control Register 0
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
FRA0
Address
0022h
After Reset
XXXX XX00b
Bit Symbol
Bit Name
Function
RW
FRA00
40 MHz on-chip oscillator start 0 : 40 MHz on-chip oscillator off
bit
1 : 40 MHz on-chip oscillator on
RW
FRA01 On-chip oscillator select bit
0 : 125 kHz on-chip oscillator
1 : 40 MHz on-chip oscillator
RW
—
(b7-b2)
No register bits. If necessary, set to 0. Read as undefined value
—
Rewrite the FRA0 register after setting the PRC0 bit in the PRCR register to 1 (write enabled).
Refer to Table 9.3 “Clock Related Bit Setting and Modes”Table 9.3 “Clock Related Bit Setting and
Modes” to select a clock and a mode.
FRA00 (40 MHz On-Chip Oscillator Start Bit) (b0)
When using an oscillation stop/re-oscillation detection interrupt, do not set the FRA00 bit to 0 (40 MHz
on-chip oscillator off), and the FRA01 bit to 1 (40 MHz on-chip oscillator).
FRA01 (40 MHz On-Chip Oscillator Select Bit) (b1)
Change the FRA01 bit if the both conditions below are met.
• When the FRA00 bit is 1 (40 MHz on-chip oscillator on) and oscillation is stable
• When the CM14 bit in the CM1 register is 0 (125 kHz on-chip oscillator on) and oscillation is stable
When setting the FRA01 bit to 0 (125 kHz on-chip oscillator), do not set the FRA00 bit to 0 (40 MHz on-
chip oscillator off) at the same time. Set the FRA00 bit to 0 after setting the FRA01 bit to 0.
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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