mirror of
https://github.com/espressif/esp-idf
synced 2025-03-10 01:29:21 -04:00
56 lines
2.3 KiB
Plaintext
56 lines
2.3 KiB
Plaintext
choice RTC_CLK_SRC
|
|
prompt "RTC clock source"
|
|
default RTC_CLK_SRC_INT_RC
|
|
help
|
|
Choose which clock is used as RTC clock source.
|
|
|
|
config RTC_CLK_SRC_INT_RC
|
|
bool "Internal 136 kHz RC oscillator"
|
|
config RTC_CLK_SRC_EXT_CRYS
|
|
bool "External 32 kHz crystal"
|
|
select ESP_SYSTEM_RTC_EXT_XTAL
|
|
endchoice
|
|
|
|
config RTC_CLK_CAL_CYCLES
|
|
int "Number of cycles for RTC_SLOW_CLK calibration"
|
|
default 3000 if RTC_CLK_SRC_EXT_CRYS
|
|
default 1024 if RTC_CLK_SRC_INT_RC
|
|
range 0 8190 if RTC_CLK_SRC_EXT_CRYS
|
|
range 0 32766 if RTC_CLK_SRC_INT_RC
|
|
help
|
|
When the startup code initializes RTC_SLOW_CLK, it can perform
|
|
calibration by comparing the RTC_SLOW_CLK frequency with main XTAL
|
|
frequency. This option sets the number of RTC_SLOW_CLK cycles measured
|
|
by the calibration routine. Higher numbers increase calibration
|
|
precision, which may be important for applications which spend a lot of
|
|
time in deep sleep. Lower numbers reduce startup time.
|
|
|
|
When this option is set to 0, clock calibration will not be performed at
|
|
startup, and approximate clock frequencies will be assumed:
|
|
|
|
- 150000 Hz if internal RC oscillator is used as clock source. For this use value 1024.
|
|
- 32768 Hz if the 32k crystal oscillator is used. For this use value 3000 or more.
|
|
In case more value will help improve the definition of the launch of the crystal.
|
|
If the crystal could not start, it will be switched to internal RC.
|
|
|
|
choice RTC_FAST_CLK_SRC
|
|
depends on SOC_CLK_LP_FAST_SUPPORT_XTAL
|
|
prompt "RTC fast clock source"
|
|
default RTC_FAST_CLK_SRC_RC_FAST
|
|
help
|
|
Choose which clock is used as RTC fast clock source.
|
|
|
|
Choosing the faster 40 MHz XTAL can allow modules which depend on RTC_FAST
|
|
to work at a higher clock frequency. With this the ULP LP-Core will run with a
|
|
CPU frequency of 40 Mhz instead of the default 20 Mhz.
|
|
|
|
The drawback is that the XTAL is usually powered down during sleep, as
|
|
it draw a lot of power. Choosing this option will cause the XTAL to stay
|
|
powered on, increasing sleep power consumption.
|
|
|
|
config RTC_FAST_CLK_SRC_RC_FAST
|
|
bool "20 Mhz RC Fast Clock"
|
|
config RTC_FAST_CLK_SRC_XTAL
|
|
bool "40 Mhz crystal (increased power consumption during sleep)"
|
|
endchoice
|