tmp19a44fda TOSHIBA Semiconductor CORPORATION, tmp19a44fda Datasheet - Page 40

• Manufacturer Part Number: tmp19a44fda
• Description: 32bit Tx System Risc
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Clock/Standby Control
5.4 System Clock Controller
(Note 1)
(Note 2)
5.4.1
5.4.2
OSCCR0<WUPT 2:0>
Warm-up time options
oscillator connection pin. The warm-up time can be selected by setting the OSCCR0<WUPT2:0> depending on the
characteristics of the oscillator. The OSCCR0<WUEON><WUEF> are used to confirm the start and completion of
warm-up through software (instruction). After the completion of warm-up is confirmed, switch the system clock
(CKSEL<SYSCK>).
CKSEL<SYSCKFLG>.
Reset initializes the system clock controller as follows.
For example, when a 10-MHz oscillator is connected to the X1 or X2 pin, fsys becomes 10MHz after reset.
The warm-up timer is provided to confirm the oscillation stability of the oscillator when it is connected to the
When clock switching occurs, the current system clock can be checked by monitoring the
(c) State Transition Diagram of BACKUP Mode
Fig. 5.1 shows the warm-up time when switching occurs.
Initial Values after Reset
Oscillation Stabilization Time (Switching between the NORMAL and SLOW modes)
000
001
010
011
100
101
110
111
Warm-up is not required when an oscillator is used for the clock and providing
stable oscillation.
The warm-up timer operates according to the oscillation clock, and it can contain
errors if there is any fluctuation in the oscillation frequency.
Therefore, the warm-up time should be taken as approximate time.
High-speed oscillator
Low-speed oscillator
PLL (phase locked loop circuit) : OFF (stop)
High-speed clock gear
Table 5.1 Warm-up Time (fosc=10 MHz, fs=32.768 kHz)
Setting prohibited
Setting prohibited
Setting prohibited
OSCCR0<WUPSEL>=“0”
frequency
frequency
frequency
frequency
2
2
2
2
High-speed clock (fosc)
13
14
15
16
－
/ input
/ input
/ input
/ input
TMP19A44(rev1.3) 5-11
: ON (oscillating)
: ON (oscillating)
: fc (no frequency dividing)
1.638（ms）
3.277（ms）
6.554（ms）
409.6（μs）
819.2（μs）
No warm-up
－
－
2
2
Setting prohibited
7
8
/ input frequency 3.906（ms）
/ input frequency 7.813（ms）
OSCCR0<WUPSEL>=“1”
frequency
frequency
frequency
frequency
2
2
2
2
Low-speed clock (fs)
15
16
17
6
/ input
－
/ input
/ input
/ input
TMP19A44
1.953（ms）
No warm-up
1.0（s）
2.0（s）
4.0（s）
－
2010-04-01