# espidf C+ bindings for **ESP-IDF** on the `esp32-xtensa` target: just enough of the platform for a control loop to drive pins, read the clock, sleep, and print. See [Embedded & ESP32](/docs/embedded) for the bigger picture. Four modules: - **`espidf/gpio`** — `reset`, `set_direction`, `set_level`, `get_level`, and the mode values. - **`espidf/timer`** — `now_us`, the `esp_timer` clock as `i64` microseconds since boot. - **`espidf/task`** — `delay_ms` / `delay_us` (newlib `usleep`, so they are tick-rate independent). - **`espidf/log`** — `print_line` / `print_i32` / `print_i64` over the UART. The `gpio` and `timer` externs are `#[no_alloc]` + `#[no_block]` leaves, so a [`#[realtime]`](/docs/realtime) control loop can call them and keep its contract. The bindings themselves stay on `i32` / `u32` / `*u8` and `#str_ptr` literals so they are usable from `#[no_alloc]` code, while `Text` / `Vec` remain available on the chip's newlib heap when you do want them. ## Building and entry point A consuming package declares `espidf = "*"` and builds as a `[lib]` staticlib: ```bash cpc build --target esp32-xtensa ``` `cpc` stops at the archive; the ESP-IDF / CMake build links the firmware (the bound symbols live in IDF's `driver`, `esp_timer`, and newlib components). The app exports `cplus_app_main`, and IDF's main component keeps a two-line C shim that calls it from `app_main`. The full entry convention is on the [Embedded & ESP32](/docs/embedded) page.