menu "Newlib" choice NEWLIB_STDOUT_LINE_ENDING prompt "Line ending for UART output" default NEWLIB_STDOUT_LINE_ENDING_CRLF help This option allows configuring the desired line endings sent to UART when a newline ('\n', LF) appears on stdout. Three options are possible: CRLF: whenever LF is encountered, prepend it with CR LF: no modification is applied, stdout is sent as is CR: each occurence of LF is replaced with CR This option doesn't affect behavior of the UART driver (drivers/uart.h). config NEWLIB_STDOUT_LINE_ENDING_CRLF bool "CRLF" config NEWLIB_STDOUT_LINE_ENDING_LF bool "LF" config NEWLIB_STDOUT_LINE_ENDING_CR bool "CR" endchoice choice NEWLIB_STDIN_LINE_ENDING prompt "Line ending for UART input" default NEWLIB_STDIN_LINE_ENDING_CR help This option allows configuring which input sequence on UART produces a newline ('\n', LF) on stdin. Three options are possible: CRLF: CRLF is converted to LF LF: no modification is applied, input is sent to stdin as is CR: each occurence of CR is replaced with LF This option doesn't affect behavior of the UART driver (drivers/uart.h). config NEWLIB_STDIN_LINE_ENDING_CRLF bool "CRLF" config NEWLIB_STDIN_LINE_ENDING_LF bool "LF" config NEWLIB_STDIN_LINE_ENDING_CR bool "CR" endchoice config NEWLIB_NANO_FORMAT bool "Enable 'nano' formatting options for printf/scanf family" default y if IDF_TARGET_ESP32C2 help In most chips the ROM contains parts of newlib C library, including printf/scanf family of functions. These functions have been compiled with so-called "nano" formatting option. This option doesn't support 64-bit integer formats and C99 features, such as positional arguments. For more details about "nano" formatting option, please see newlib readme file, search for '--enable-newlib-nano-formatted-io': https://sourceware.org/newlib/README If this option is enabled and the ROM contains functions from newlib-nano, the build system will use functions available in ROM, reducing the application binary size. Functions available in ROM run faster than functions which run from flash. Functions available in ROM can also run when flash instruction cache is disabled. Some chips (e.g. ESP32-C6) has the full formatting versions of printf/scanf in ROM instead of the nano versions and in this building with newlib nano might actually increase the size of the binary. Which functions are present in ROM can be seen from ROM caps: ESP_ROM_HAS_NEWLIB_NANO_FORMAT and ESP_ROM_HAS_NEWLIB_NORMAL_FORMAT. If you need 64-bit integer formatting support or C99 features, keep this option disabled. choice NEWLIB_TIME_SYSCALL prompt "Timers used for gettimeofday function" default NEWLIB_TIME_SYSCALL_USE_RTC_HRT help This setting defines which hardware timers are used to implement 'gettimeofday' and 'time' functions in C library. - If both high-resolution (systimer for all targets except ESP32) and RTC timers are used, timekeeping will continue in deep sleep. Time will be reported at 1 microsecond resolution. This is the default, and the recommended option. - If only high-resolution timer (systimer) is used, gettimeofday will provide time at microsecond resolution. Time will not be preserved when going into deep sleep mode. - If only RTC timer is used, timekeeping will continue in deep sleep, but time will be measured at 6.(6) microsecond resolution. Also the gettimeofday function itself may take longer to run. - If no timers are used, gettimeofday and time functions return -1 and set errno to ENOSYS. - When RTC is used for timekeeping, two RTC_STORE registers are used to keep time in deep sleep mode. config NEWLIB_TIME_SYSCALL_USE_RTC_HRT bool "RTC and high-resolution timer" select ESP_TIME_FUNCS_USE_RTC_TIMER select ESP_TIME_FUNCS_USE_ESP_TIMER config NEWLIB_TIME_SYSCALL_USE_RTC bool "RTC" select ESP_TIME_FUNCS_USE_RTC_TIMER config NEWLIB_TIME_SYSCALL_USE_HRT bool "High-resolution timer" select ESP_TIME_FUNCS_USE_ESP_TIMER config NEWLIB_TIME_SYSCALL_USE_NONE bool "None" select ESP_TIME_FUNCS_USE_NONE endchoice endmenu # Newlib