Toshiba TLCS-900/L1 Series Manual page 22

Example 2: Setting the clock
Changing from low frequency (fs) to high frequency (fc).
SYSCR0 EQU
SYSCR1 EQU
SYSCR2 EQU
LD
SET
SET
WUP: BIT
JR
RES
RES
X: Don't care, −: No change
<XEN>
X1, X2 pins
<XTEN>
XT1, XT2 pins
Warm-up timer
Counts up by f
End of warm-up timer
<SYSCK>
System clock f
SYS
Enables
high frequency
00E0H
00E1H
00E2H
(SYSCR2), X−10− − − −B ; Sets warm-up time to 214/fc.
7, (SYSCR0) ; Enables high-frequency oscillation.
2, (SYSCR0) ; Clears and starts warm-up timer.
2, (SYSCR0) ;
Detects stopping of warm-up timer.
NZ, WUP ;
3, (SYSCR1) ; Changes fSYS from fs to fc.
6, (SYSCR0) ; Disables low-frequency oscillation.
Counts up by f
SYS
fs
Clears and starts
warm-up timer
End of warm-up
timer
91C824-20
OSCH
fc
Chages f
SYS
from fs to fc
Disables
low frequency
TMP91C824
2008-02-20