The Setting Method Of A System Clock - Toshiba TXZ+ Series Reference Manual

1.2.6.1. The setting method of a system clock

setup (internal oscillation → external oscillation)
(1) f
OSC
As a f setup, the example of switching procedure to the external oscillation (EHOSC) from an internal
OSC
oscillation (IHOSC1) is shown below.
[CGOSCCR]<IHOSC1EN> = 1
[CGOSCCR]<OSCSEL> = 0
[CGOSCCR]<OSCF> = 0
An oscillator is connected to X1/X2 pin. (Note)
Note: Do not connect except a resonator.
[PHPDN]<bit[1:0]> = 00
1
[PHIE]<bit[1:0]> = 00
[CGOSCCR]<EOSCEN[1:0]> = 01
2
[CGWUPHCR]<WUCLK> = 1
3 [CGWUPHCR]<WUPT[18:4]> = "arbitrary
value"
4 [CGWUPHCR]<WUON> = 1
5 [CGWUPHCR]<WUEF> is read.
6 [CGOSCCR]<OSCSEL> = 1
7 [CGOSCCR]<OSCF> is read.
8 [CGOSCCR]<IHOSC1EN> = 0
setup ( internal oscillation → external clock input)
(2) f
OSC
As a f setup, the example of switching procedure to the external clock input (EHCLKIN) from an internal
OSC
oscillation 1 (IHOSC1) is shown below.
[CGOSCCR]<IHOSC1EN> = 1
[CGOSCCR]<OSCSEL> = 0
[CGOSCCR]<OSCF> = 0
Clock input to EHCLKIN
[PHPDN]<bit[0]> = 0
1
[PHIE]<bit[0]> = 1
2 [CGOSCCR]<EOSCEN[1:0]> = 10
3 [CGOSCCR]<OSCSEL> = 1
4 [CGOSCCR]<OSCF> is read.
[CGOSCCR]<IHOSC1EN> = 0
5
<<The state before switching>>
An internal high speed oscillator 1 oscillates.
The high speed oscillation selection for f
The high speed oscillation selection status for f
(IHOSC1).
<<The example of switching procedure>>
Disable the pull-down of X1/X2 pin.
Disable input control of X1/X2 pin.
It is an external oscillation (EHOSC) about selection of an external
oscillation of operation.
It is the external (EHOSC) about high speed oscillation warming up
clock selection.
Oscillator stable time is set to a warming up timer setting value.
High speed oscillation warming up is started.
It waits until it becomes the termination of high speed oscillation
warming up (= 0).
It is high speed oscillation selection for f
It waits until the high speed oscillation selection status for f
becomes outside (= 1).
An internal high speed oscillator 1 is suspended.
<<The state before switching>>
An internal high speed oscillator 1 oscillates.
The high speed oscillation selection for f
The high speed oscillation selection status for f
(IHOSC1).
Input in the proper voltage range.
<<The example of switching procedure>>
Disable the pull-down of X1 pin.
Enable the input control of an X1/EHCLKIN pin.
Selection of an external oscillation of operation is carried out to an
external clock input (EHCLKIN).
It is high speed oscillation selection for f
It waits until the high speed oscillation selection status for f
becomes outside (= 1).
An internal high speed oscillator 1 is suspended.
19 / 72
TMPM3H Group(1)
Clock Control and Operation Mode
is an inside (IHOSC1).
OSC
OSC
to the exterior (EHOSC).
OSC
is an inside (IHOSC1).
OSC
OSC
to an external clock.
OSC
TXZ+ Family
is an inside
OSC
is an inside
OSC
2022-05-10
Rev. 1.3