ESPNOW is a kind of WiFi communication bettween WiFi devices, no
matter they are connected to each other or not. Once two WiFi
devices are paired, they can send data to or receive data from
each other. The data is transmitted in action frame which can
be encrypted with CCMP method. ESPNOW also support mutilcast frame
transmitting.
All peripheral clocks are default enabled after chip is powered on.
When CPU starts, if reset reason is CPU reset, disable those clocks
that are not enabled before reset. Otherwise, disable all those
useless clocks.
These peripheral clocks must be enabled when the peripherals are
initialized and disabled when they are deinitialized.
1. Hello World application shows no footprint difference before and
after this change
2. examples/ethernet/ethernet application compiles properly (can't
test with my board)
This is no longer required since the functions automatically get
pulled in based on the usage. A quick summary of footprint
comparisions before and after these set of patches is shown below:
Hello-World: (simplified for readability)
old Total image size:~ 104902 bytes (.bin may be padded larger)
old Total image size:~ 105254 bytes (.bin may be padded larger)
Per-archive contributions to ELF file:
Archive File DRAM .data & .bss IRAM Flash code & rodata Total
old libesp32.a 1973 177 4445 3939 2267 12801
new libesp32.a 1973 185 4473 3939 2267 12837
new libnvs_flash.a 0 92 0 274 8 374
new libstdc++.a 0 0 0 24 0 24
For some reason, nvs_flash.a (~400bytes) gets pulled in (particularly
the nvs_flash_init() function).
Power-Save: (simplified for readability)
old Total image size:~ 421347 bytes (.bin may be padded larger)
old Total image size:~ 421235 bytes (.bin may be padded larger)
old libtcpip_adapter.a 0 81 0 1947 115 2143
new libtcpip_adapter.a 0 69 0 1897 115 2081
The size actually shrinks a bit, since the AP interface function
doesn't get pulled in.
Restart being a lower-layer system-level function, needn't depend on
the higher level Wi-Fi libraries.
This also enables us to get rid of one more WIFI_ENABLED ifdef check
Because of errata related to BOD reset function, brownout is handled as follows:
- attach an ISR to brownout interrupt
- when ISR happens, print a message and do a software restart
- esp_restart_nonos enables RTC watchdog, so if restart fails,
there will be one more attempt to restart (using the RTC
watchdog)
Implements support for system level traces compatible with SEGGER
SystemView tool on top of ESP32 application tracing module.
That kind of traces can help to analyse program's behaviour.
SystemView can show timeline of tasks/ISRs execution, context switches,
statistics related to the CPUs' load distribution etc.
Also this commit adds useful feature to ESP32 application tracing module:
- Trace data buffering is implemented to handle temporary peaks of events load
Small changes to clock calibration value will cause increasing errors
the longer the device runs. Consider the case of deep sleep, assuming
that RTC counter is used for timekeeping:
- before sleep:
time_before = rtc_counter * calibration_val
- after sleep:
time_after = (rtc_counter + sleep_count) * (calibration_val + epsilon)
where 'epsilon' is a small estimation error of 'calibration_val'.
The apparent sleep duration thus will be:
time_after - time_before = sleep_count * (calibration_val + epsilon)
+ rtc_counter * epsilon
Second term on the right hand side is the error in time difference
estimation, it is proportional to the total system runtime (rtc_counter).
To avoid this issue, this change makes RTC_SLOW_CLK calibration value
persistent across restarts. This allows the calibration value update to
be preformed, while keeping time after update same as before the update.
DPORT access protection can not work when the other CPU is stalled.
Writes to DPORT registers in esp_restart caused the program to hang due
to access protection, and the reset happened due to RTC_WDT, not SW_RST.
This change adds esp_dport_access_int_deinit function and calls it from
esp_restart once the other core is stalled.
