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| TMP86CM49FG Datasheet, PDF (42/252 Pages) Toshiba Semiconductor – 8 Bit Microcontroller | |||
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2. Operational Description
2.2 System Clock Controller
TMP86CM49FG
2.2.4.4 SLOW mode
SLOW mode is controlled by the system control register 2 (SYSCR2).
The following is the methods to switch the mode with the warm-up counter.
(1) Switching from NORMAL2 mode to SLOW1 mode
First, set SYSCR2<SYSCK> to switch the main system clock to the low-frequency clock for
SLOW2 mode. Next, clear SYSCR2<XEN> to turn off high-frequency oscillation.
Note: The high-frequency clock can be continued oscillation in order to return to NORMAL2 mode from
SLOW mode quickly. Always turn off oscillation of high-frequency clock when switching from
SLOW mode to stop mode.
Example 1 :Switching from NORMAL2 mode to SLOW1 mode.
SET
(SYSCR2). 5
; SYSCR2<SYSCK> â 1
(Switches the main system clock to the low-frequency
clock for SLOW2)
CLR
(SYSCR2). 7
; SYSCR2<XEN> â 0
(Turns off high-frequency oscillation)
Example 2 :Switching to the SLOW1 mode after low-frequency clock has stabilized.
SET
(SYSCR2). 6
; SYSCR2<XTEN> â 1
LD
(TC5CR), 43H
; Sets mode for TC6, 5 (16-bit mode, fs for source)
LD
(TC6CR), 05H
; Sets warming-up counter mode
LDW
DI
(TTREG5), 8000H
; Sets warm-up time (Depend on oscillator accompanied)
; IMF â 0
SET
(EIRE). 2
EI
; Enables INTTC6
; IMF â 1
SET
(TC6CR). 3
; Starts TC6, 5
:
PINTTC6:
CLR
SET
CLR
(TC6CR). 3
(SYSCR2). 5
(SYSCR2). 7
; Stops TC6, 5
; SYSCR2<SYSCK> â 1
(Switches the main system clock to the low-frequency clock)
; SYSCR2<XEN> â 0
(Turns off high-frequency oscillation)
RETI
:
VINTTC6:
DW
PINTTC6
; INTTC6 vector table
Page 28
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