UPD78F1502AGK-GAK-AX Datasheet, PDF (231/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 5 CLOCK GENERATOR
Figure 5-5. Format of Oscillation Stabilization Time Select Register (OSTS)
Address: FFFA3H After reset: 07H R/W
Symbol
7
6
5
4
3
2
1
OSTS
0
0
0
0
0
OSTS2
OSTS1
0
OSTS0
OSTS2
0
0
0
0
1
1
1
1
OSTS1
0
0
1
1
0
0
1
1
OSTS0
0
2⁸/fX
1
2⁹/fX
0
2¹⁰/fX
1
2¹¹/fX
0
2¹³/fX
1
2¹⁵/fX
0
2¹⁷/fX
1
2¹⁸/fX
Oscillation stabilization time selection
fX = 10 MHz
fX = 20 MHz
25.6 μs
Setting prohibited
51.2 μs
25.6 μs
102.4 μs
51.2 μs
204.8 μs
102.4 μs
819.2 μs
409.6 μs
3.27 ms
1.64 ms
13.11 ms
6.55 ms
26.21 ms
13.11 ms
Cautions 1. To set the STOP mode when the X1 clock is used as the CPU clock, set the OSTS
register before executing the STOP instruction.
2. Setting the oscillation stabilization time to 20 μs or less is prohibited.
3. To change the setting of the OSTS register, be sure to confirm that the counting
operation of the OSTC register has been completed.
4. Do not change the value of the OSTS register during the X1 clock oscillation
stabilization time.
5. The oscillation stabilization time counter counts up to the oscillation stabilization
time set by OSTS.
In the following cases, set the oscillation stabilization time of OSTS to the value
greater than the count value which is to be checked by the OSTC register after the
oscillation starts.
• If the X1 clock starts oscillation while the internal high-speed oscillation clock or
subsystem clock is being used as the CPU clock.
• If the STOP mode is entered and then released while the internal high-speed
oscillation clock is being used as the CPU clock with the X1 clock oscillating.
(Note, therefore, that only the status up to the oscillation stabilization time set by
OSTS is set to OSTC after the STOP mode is released.)
6. The X1 clock oscillation stabilization wait time does not include the time until clock
oscillation starts (“a” below).
STOP mode release
X1 pin voltage
waveform
a
Remark fX: X1 clock oscillation frequency
R01UH0004EJ0501 Rev.5.01
215
Jun 20, 2011