TMP86CH21AUG Datasheet, PDF (129/188 Pages) Toshiba Semiconductor – 8 Bit Microcontroller

TMP86CH21AUG
10.3.8.2 High-Frequency Warm-Up Counter Mode
(SLOW1 → SLOW2 → NORMAL2 → NORMAL1)
In this mode, the warm-up period time from a stop of the high-frequency clock fc to the oscillation sta-
bility is obtained. Before starting the timer, set SYSCR2<XEN> to 1 to oscillate the high-frequency clock.
When a match between the up-counter and the timer register (TTREG6, 5) value is detected after the timer
is started by setting TC6CR<TC6S> to 1, the counter is cleared by generating the INTTC6 interrupt
request. After stopping the timer in the INTTC6 interrupt service routine, clear SYSCR2<SYSCK> to 0 to
switch the system clock from the low-frequency to high-frequency, and then SYSCR2<XTEN> to 0 to
stop the low-frequency clock.
Table 10-9 Setting Time in High-Frequency Warm-Up Counter Mode
Minimum time (TTREG6, 5 = 0100H)
16 µs
Maximum time (TTREG6, 5 = FF00H)
4.08 ms
Example :After checking high-frequency clock oscillation stability with TC6 and 5, switching to the NORMAL1 mode
SET
(SYSCR2).7
: SYSCR2<XEN> ← 1
LD
(TC5CR), 63H
: Sets TFF5=0, source clock fs, and 16-bit mode.
LD
(TC6CR), 05H
: Sets TFF6=0, and warm-up counter mode.
LD
(TTREG5), 0F800H
: Sets the warm-up time.
(The warm-up time depends on the oscillator characteristic.)
DI
: IMF ← 0
SET
(EIRH). 4
: Enables the INTTC6.
EI
: IMF ← 1
SET
(TC6CR).3
: Starts the TC6 and 5.
:
:
PINTTC6:
CLR
(TC6CR).3
: Stops the TC6 and 5.
CLR
(SYSCR2).5
: SYSCR2<SYSCK> ← 0
(Switches the system clock to the high-frequency clock.)
CLR
(SYSCR2).6
: SYSCR2<XTEN> ← 0
(Stops the low-frequency clock.)
RETI
:
:
VINTTC6:
DW
PINTTC6
: INTTC6 vector table
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