Toshiba TLCS-870/C Series Manual page 44

(2) Switching from SLOW1 mode to NORMAL2 mode
First, set SYSCR2<XEN> to turn on the high-frequency oscillation. When time for stabilization
(Warm up) has been taken by the timer/counter (TC4,TC3), clear SYSCR2<SYSCK> to switch the
main system clock to the high-frequency clock.
SLOW mode can also be released by inputting low level on the
operation mode is started from NORMAL1 mode.
Note: After SYSCK is cleared to "0", executing the instructions is continiued by the low-frequency clock
for the period synchronized with low-frequency and high-frequency clocks.
High-frequency clock
Low-frequency clock
Main system clock
SYSCK
Example :Switching from the SLOW1 mode to the NORMAL2 mode (fc = 16 MHz, warm-up time is 4.0 ms).
SET
LD
LD
LD
DI
SET
EI
SET
:
PINTTC4: CLR
CLR
RETI
:
VINTTC4: DW
(SYSCR2). 7
; SYSCR2<XEN>
(TC3CR), 63H ; Sets mode for TC4, 3 (16-bit mode, fc for source)
(TC4CR), 05H ; Sets warming-up counter mode
(TTREG4), 0F8H ; Sets warm-up time
←
; IMF
(EIRH). 3 ; Enables INTTC4
←
; IMF
(TC4CR). 3 ; Starts TC4, 3
(TC4CR). 3 ; Stops TC4, 3
(SYSCR2). 5 ; SYSCR2<SYSCK>
(Switches the main system clock to the high-frequency clock)
PINTTC4 ; INTTC4 vector table
Page 29
pin. After releasing reset, the
RESET
←
1 (Starts high-frequency oscillation)
0
1
←
0
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