TMP91C824
91C824-14
2008-02-20
3.3.1
Block Diagram of System Clock
Figure 3.3.2 Block Diagram of System Clock
Clock gear
SYSCR1<SYSCK>
TMRA0 to TMRA3
SYSCR0
<PRCK1:0>
Selector
fs
f
OSCH
Low-frequency
oscillator
XT1
XT2
SYSCR0
<XTEN, RXTEN>
Warm-up timer (High-/low-frequency
oscillator), Lockup timer (DFM)
SYSCR0<WUEF>
SYSCR2<WUPTM1:0>
DFMCR0<ACT1:0, DLUPTM>
X1
X2
Clock doubler
(DFM)
f
DFM
=
f
OSCH
×
4
÷
2
÷
16
÷
4
fc/16
fc/8
fc/4
fc/2
fc
DFMCR0<ACT1:0>
SYSCR1<GEAR2, 0>
÷
2
÷
4
fc/16
f
FPH
f
SYS
÷
2
f
SYS
CPU
RAM
ADC
Interrupt
controller
WDT
I/O ports
Prescaler
φ
T0
SIO0 to SIO1
SBI
RTC
φ
T
fs
φ
T0
fs
φ
T
SYSCR0
<XEN, RXEN>
High-frequency
oscillator
÷
8
Prescaler
MLD/ALM
CS/WAIT
Controller