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MAX32660 User Guide
Maxim Integrated
Page 22 of 195
The following steps describe how to change the OVR:
1.
Ensure the part is operating from the internal LDO for V
CORE
.
a.
Set
ldo_dis
to 0.
b.
If using an external supply for V
CORE
, ensure the external supply is set to the same voltage as the current OVR
setting. The external supply must be equal to or greater than the set OVR voltage.
2.
Set either the 32.768kHz external oscillator or 8kHz nano-ring oscillator as the system clock source.
a.
Oscillator Sources and System Clock Selection
for details on system clock selection.
3.
Set the number of Flash Wait States to the POR default value of 5.
a.
fw
= 5
4.
Change the OVR setting to the desired range.
a.
Set
ovr
to either 0, 1, or 2 as shown in
5.
Set the Flash Low Voltage Enable according to the OVR setting set in step 4.a.
a.
Set
lve
to either 0 or 1 as required. Reference
for the required value.
6.
If desired, set the system clock source to the HFIO and update the system clock prescaler to the desired value.
a.
Set
clksel
= 0.
b.
Wait for the system clock ready bit,
clkrdy,
to read 1
.
c.
Set
psc
to the desired prescaler value.
7.
Set the number of Flash Wait States per
a.
Set
fws
to the minimum value shown for the selected OVR and System Clock
8.
Perform a Peripheral Reset.
a.
Set
.periph_rst
= 1.
On each subsequent reset event:
1.
ovr
is set to 0, set the flash low voltage enable bit to 1 (
lve
= 1)
2.
.psc
, as needed by the system.
3.
Set the number of flash wait states,
fws
, as needed based on the OVR settings using
4.1.2
Flash Wait States
Power-On Reset, System Reset and Watchdog Reset all reset the Flash Wait State field,
fws
, to the POR
default setting of 5. The Flash Wait State field is the number of system clock cycles for accessing the internal flash memory
and is dependent on the OVR settings, the system oscillator selected and the system oscillator prescaler.
The setting for the number of flash wait states effects performance and it is critical to set it correctly based on the OVR
settings and the system clock frequency. Set the number of flash wait states using the field
fws
per
. The
fws
field should always be set to the default POR reset value of 5 prior to changing the
ovr
settings.
Important:
Flash reads may fail and result in unknown instruction execution if the Flash Wait State setting is lower than the
minimum required for a given OVR setting and the selected system clock frequency.
Содержание MAX32660
Страница 4: ...MAX32660 User Guide Maxim Integrated Page 4 of 195 8 UART 84 9 Real Time Clock RTC 96 10 Timers 105...
Страница 7: ...MAX32660 User Guide Maxim Integrated Page 7 of 195 15 Trademarks 195 16 Revision History 195...
Страница 14: ...MAX32660 User Guide Maxim Integrated Page 14 of 195 Figure 2 1 MAX32660 High Level Block Diagram...