Operation - Panasonic MN101L Series User Manual

4.3.4

Operation

Voltage Transition of VDD18 by Program
Figure:4.3.1 shows the example of voltage transition of VDD18 by program.
When SLOW mode, the PWCTR0.VDDLV1-0 are set to change the output voltage, VDD18 and achieve low-
power consumption or high-speed operation depending on the operating frequency.
Voltage transition cannot be set in NORMAL mode. It is also impossible to change the voltage from 1.3 V to 1.8
V and from 1.8 V to 1.3 V. After updating the PWCTR0.VDDLV1-0, CPU clock is halted for the time set in the
PWCTR1.PWUPTM2-0 while the voltage is boosted during i) and iii) shown in the Figure:4.3.1. Although CPU
clock is not halted while the voltage is stepped down during ii) and iv) shown in the Figure:4.3.1, it does not affect
the operation.
V
DD30
1.8 V
1.3 V
1.1 V
Power ON
VDDLV1-0
VDD18 output
Operating mode
MAX operating speed
The setting example to change VDD18 from 1.1 V to 1.8 V at iii) in Figure:4.3.1 is shown below.
CPU outage in voltage transition: 32/f
Step Setting
Set CPU outage in voltage transition
1
2 Set output voltage, VDD18
3 NOP instruction
4 Transition to NORMAL mode
Be sure to execute the setting in SLOW mode.
.. ..
VDD30
00
1.1 V
SLOW
CPU idle time
40 kHz
Figure:4.3.1 Voltage Transition of VDD18 by Program
= 32.768 kHz, 977 µs)
(f
SCLK SCLK
Register name
PWCTR1
PWCTR0
VDD18 output voltage
ii)
i)
01 00
1.3 V 1.1 V
NORMAL SLOW
1 MHz
40 kHz
Set PWUPTM2-0 to "011".
Set VDDLV1-0 to "10".
- Insert 3 NOP instructions.
CPUM Set to "00000111".
Clock/ Mode/ Voltage Control
iii) iv)
10 00
1.8 V 1.1 V
CPU idle time
NORMAL SLOW
40 kHz
10 MHz
Description
Voltage Control
Chapter 4
IV - 29