If the RTC crystal is bad or has no matched capacitance, then you do not need to start such the crystal. It is necessary to determine this case, output an error (about impossibility to start from the oscillator) and start from the internal RC of the chain.
Reduced the default value of the number of bootstrap cycles. Because we can oscillating the oscillator which then stops. (in Kconfig). Changed from 100 to 5.
The number of calibration cycles has been increased. It is the main criterion for estimating the launch of an oscillator. A large increase leads to an increase in the load time, as well as the stability of recognition of this case. (in Kconfig).
Changed from 1024 to 3000.
1. External 32kHz crystal is started for too long or it may not start at all. It is often observed at the first start.
2. At the first start, it is possible that the crystal did not start. And the recorded period was recorded as 0. Which led to a division error by zero during the transition to the deep sleep mode (Maybe somewhere else).
3. Added a unit test to test a new method of oscillation an external crystal.
4. Added a new method of oscillating of an external crystal. The legs of the crystal are fed with a 32 kHz frequency.
The new method eliminates these errors.
Added unit test: `\esp-idf\components\soc\esp32\test\test_rtc_clk.c`: `make TEST_COMPONENTS=soc`
- 8 Test starting external RTC crystal. Will pass.
`Bootstrap cycles for external 32kHz crystal` - is specified in the file Kconfig by default 100.
QA tested a new method of oscillation the crystal on 25 boards. The supply of square waves on the crystal showed a 100% result in contrast to the previous method of launching the crystal. After the tests, the old method was deleted.
Closes TW19143
ROM code already implements XTAL frequency detection, but it uses the 8M
clock before the clock tuning parameters are initialized. With the
zero clock tuning parameter, 8M clock has significant frequency deviation
at high temperatures, which can lead to erroneous detection of 40 MHz
crystal as a 26 MHz one.
This change adds XTAL frequency detection code to rtc_clk_init routine,
and detection is performed after the 8M clock tuning parameter as been
initialized.
