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esp32: add support for 8MD256 and external 32k as slow clock options

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This commit is contained in:
Ivan Grokhotkov
2018-08-13 01:12:01 +03:00
parent 5bf3654637
commit 96971e3e9f
2 changed files with 57 additions and 10 deletions
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23
components/esp32/Kconfig
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@@ -683,18 +683,39 @@ choice ESP32_RTC_CLOCK_SOURCE
default ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC
help
Choose which clock is used as RTC clock source.
- "Internal 150kHz oscillator" option provides lowest deep sleep current
consumption, and does not require extra external components. However
frequency stability with respect to temperature is poor, so time may
drift in deep/light sleep modes.
- "External 32kHz crystal" provides better frequency stability, at the
expense of slightly higher (1uA) deep sleep current consumption.
- "External 32kHz oscillator" allows using 32kHz clock generated by an
external circuit. In this case, external clock signal must be connected
to 32K_XP pin. Amplitude should be <1.2V in case of sine wave signal,
and <1V in case of square wave signal. Common mode voltage should be
0.1 < Vcm < 0.5Vamp, where Vamp is the signal amplitude.
Additionally, 1nF capacitor must be connected between 32K_XN pin and
ground. 32K_XN pin can not be used as a GPIO in this case.
- "Internal 8.5MHz oscillator divided by 256" option results in higher
deep sleep current (by 5uA) but has better frequency stability than
the internal 150kHz oscillator. It does not require external components.
config ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC
bool "Internal 150kHz RC oscillator"
config ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL
bool "External 32kHz crystal"
config ESP32_RTC_CLOCK_SOURCE_EXTERNAL_OSC
bool "External 32kHz oscillator at 32K_XP pin"
config ESP32_RTC_CLOCK_SOURCE_INTERNAL_8MD256
bool "Internal 8.5MHz oscillator, divided by 256 (~33kHz)"
endchoice
config ESP32_RTC_CLK_CAL_CYCLES
int "Number of cycles for RTC_SLOW_CLK calibration"
default 3000 if ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL
default 1024 if ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC
range 0 27000 if ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL
range 0 27000 if ESP32_RTC_CLOCK_SOURCE_EXTERNAL_CRYSTAL || ESP32_RTC_CLOCK_SOURCE_EXTERNAL_OSC || ESP32_RTC_CLOCK_SOURCE_INTERNAL_8MD256
range 0 32766 if ESP32_RTC_CLOCK_SOURCE_INTERNAL_RC
help
When the startup code initializes RTC_SLOW_CLK, it can perform