Module `esp_idf_nvs_flash` uses C++ code. Since `esp_idf_nvs_flash` module is always enabled on ESP8266, the permanent dependency on `cpp` is correct. But on ESP32, the `esp_idf_nvs_flash` module is only enabled if `esp_wifi_any` is used. Only in that case the compilation should depend on module `cpp`.
The former correction factors were determined by measuring the resulting clocks without a device connected to the bus.
However, when testing the changes for low CPU clock frequencies, it was figured out that the clocks not only depend on configured register values
_i2c_hw[dev].regs->scl_low_period.period
_i2c_hw[dev].regs->scl_high_period.period
but also on the bus capacity. Obviously, the register values are not absolute times in APB clock cycles, but rather times that start as soon as the corresponding level is reached. In this case, the higher the bus capacity, the longer the period would be.
This means that the clock speed cannot be precisely controlled via the correction factors anyway. For this reason, and because the I2C implementation in ESP-IDF also does not use correction factors, they were removed.
The semantics of defining an SSID prefix that overrides the already defined SSID exactly when and only when it is set, and then enabling dynamic SSID generation with that prefix, made handling the parameter definition unnecessarily difficult and hard to understand.
Defining a boolean option that enables dynamic SSID generation, which then simply reuses the defined SSID as a prefix, makes it much more understandable and easier to handle, especially with respect to Kconfig.
With the change from using archive files to using object files in PR #14754, the module `esp_wifi_enterprise` was no longer compilable. The reason for this was that the file `bignum.c` was present in two different vendor sub-directories and created two identical object files, which then led to a symbol conflict when linking. This commit removes one of these identical files. The one that is used in all `esp_wifi` variants is kept, the one that is only used in `esp_wifi_enterprise` is dropped.
The IRAM is much faster, while the IROM is much slower and can only be accessed via a cache, which is also sometimes disabled, e.g. by the WiFi module or when writing to the flash. Therefore, time-critical code as well as code that has to work even when the cache is disabled must be placed in the IRAM.
Checksumming flash is not supported on xtensa platform:
Warn : not implemented yet
make: *** [.../RIOT/examples/saul/../../Makefile.include:796: flash] Error 1
https://github.com/espressif/openocd-esp32 is needed.
Example config (when compiled from source):
export OPENOCD="~/esp/openocd-esp32/src/openocd -s ~/esp/openocd-esp32/tcl"
If esp_idf_heap is not used, implement calloc through a custom wrapper
function on top of malloc to add overflow detection, which is not
present in the newlib forks with xtensa support yet.
