By using a custom EPOCH for the RTC implementation, we can extend the
range of the 32 bit counter based RTC by 118 years.
It also reduces the code size compared to the stdlib based POSIX functions.
- Unecessary definitions are removed.
- Since the 48-bit RTC hardware timer uses a RC oscillator as clock, it is pretty inaccurate and leads to a RTC time deviation of up to 3 seconds per minute. Therefore, a calibration during the boot time determines a correction factor for the 48-bit RTC hardware timer. Function _rtc_time_to_us uses now this correction factor and converts a raw 48-bit RTC time to a corrected time in microseconds. Thus, the 48-bit RTC timer becomes much more accurate, but it can't still reach the accuracy of the PLL driven 64-bit system timer. The Advantage of using RTC over 64-bit sydtem timer is that it also continues in deep sleep mode and after software reset.
- If the 64-bit system timer is used to emulate the RTC timer, it uses the RTC hardware timer to continue its operation after software .
It is possible to use different timers as RTC timer for the periph_rtc module. Either the 48-bit RTC hardware timer is used directly or the PLL driven 64-bit system timer emulates a RTC timer. The latter one is much more accurate. Pseudomodule esp_rtc_timer controlls which timer is used. Only if esp_rtc_timer is enabled explicitly, the 48-bit RTC hardware timer is used. Otherwise the 64-bit sytstem timer is used to emulate the RTC timer.
Startup information, including board configuration, is only printed when module esp_log_startup is used. This reduces the amount of information that is printed by default to the console during the startup. The user can enable module esp_log_startup to get the additional startup information.
If `SPI_CS_UNDEF` is given as the `cs` parameter, CS pin must not be handled by the driver. Furthermore, if `cont` parameter is true, CS pin must not be disabled at the end of one transfer.
While deleting multiple sectors in flash, interrupts were disabled over the whole time. Thus, deleting the entire flash led to the triggering of the watchdog timer and thus to a restart. Therefore, the interrupts and the cache are disabled only for the time of deleting a single sector. The same problem occurred for read and write large data sets.
Although it isn't explicitly specified in API, gpio_read should return the last written output value for output ports. Since the handling of inputs and outputs is strictly separated by several registers in ESP32, gpio_read returned always the initial value of the input register. Therefore, a case distinction had to make. While for input ports the real value has to be read from the input register, the last written value for the output port has to be read from the output register.
UART devices are now configured using static array in header files instead of static variables in implementation to be able to define UART_NUMOF using the size of the array instead of a variable.
SPI devices are now configured using static array in header files instead of static variables in implementation to be able to define SPI_NUMOF using the size of the array instead of a variable.
I2C devices are now configured using static array in header files instead of static variables in implementation to be able to define I2C_NUMOF using the size of the array instead of a variable.
DAC pins are now configured using static arrays in header files instead of static variables in implementation to be able to define DAC_NUMOF using the size of these arrays instead of a variable.
ADC pins are now configured using static arrays in header files instead of static variables in implementation to be able to define ADC_NUMOF using the size of these arrays instead of a variable.
Functions that are used by ADC and DAC peripherals are moved to a new submodule periph_adc_ctrl. This is necessary to compile separate submodules for ADC and DAC.
The GPIO for RX has to be initialized as input before the GPIO for TX can be initialized as output. Otherwise it could lead to creash if RX GPIO was used as output before.
Function uart_set_baudrate which is only used internally was made static and renamed to _uart_set_baudrate to indicate that it is an internal function. Furthermore, an additional waiting for flushed TX FIFO added. The reconfiguration is now handled as critical section.
