Sudeep Mohanty
53ea9b200e
The subproject knows which architecture it builds for, so a ULP program names only its own dependencies.
| Supported Targets | ESP32-S2 | ESP32-S3 |
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ULP RISC-V Build System Example
This example demonstrates a separate ULP RISC-V project built with the CMake v2 ULP project helpers. It programs the ULP RISC-V coprocessor to increment a counter while the main CPUs are in deep sleep, then wake the main CPU after a fixed number of timer iterations.
ULP program written in C can be found in main/ulp/main/main.c. The build system compiles and links this program, converts it into binary format, and embeds it into the .rodata section of the ESP-IDF application.
At runtime, the application running inside the main CPU loads ULP program into the RTC_SLOW_MEM memory region using ulp_riscv_load_binary function. The main code then configures the ULP wakeup period and starts the coprocessor by using ulp_riscv_run. Once the ULP program is started, it runs periodically, with the period set by the main program. The main program enables ULP wakeup source and puts the chip into deep sleep mode.
On each timer iteration, the ULP program increments iteration_count. Once this counter reaches wakeup_iteration (set by the main program), the ULP sends a wakeup signal to the main CPU. Upon wakeup, the main program stops the ULP timer, prints the final counter value, and exits the example.
Example output
Not a ULP-RISC-V wakeup, initializing it!
Entering deep sleep
ULP-RISC-V woke up the main CPU!
ULP-RISC-V iteration count: 5
Example finished