fix(bitscrambler): example timeout in the bsasm

also added example pytest

docs/en/api-reference/peripherals/bitscrambler.rst

@@ -193,6 +193,10 @@ Resource allocation and program loading
 
 In loopback mode, a BitScrambler object is created using :cpp:func:`bitscrambler_loopback_create`. If there is a BitScrambler peripheral matching the requested characteristics, this function will return a handle to it. You can then use :cpp:func:`bitscrambler_load_program` to load a program into it, then call :cpp:func:`bitscrambler_loopback_run` to transform a memory buffer using the loaded program. You can call :cpp:func:`bitscrambler_loopback_run` any number of times; it's also permissible to use :cpp:func:`bitscrambler_load_program` to change programs between calls. Finally, to free the hardware resources and clean up memory, call :cpp:func:`bitscrambler_free`.
 
+Application Example
+-------------------
+
+* :example:`peripherals/bitscrambler` demonstrates how to use the BitScrambler loopback mode to transform a buffer of data into a different format.
 
 API Reference
 -------------

examples/peripherals/bitscrambler/CMakeLists.txt

@@ -5,4 +5,8 @@
 cmake_minimum_required(VERSION 3.16)
 
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+# "Trim" the build. Include the minimal set of components, main, and anything it depends on.
+idf_build_set_property(MINIMAL_BUILD ON)
+
 project(bitscrambler_example)

examples/peripherals/bitscrambler/README.md

@@ -23,6 +23,15 @@ See the Getting Started Guide for full steps to configure and use ESP-IDF to bui
 
 ## Example Output
 
+```text
+I (305) bs_example: BitScrambler example main
+BitScrambler program complete. Input 40, output 40 bytes:
+FF 00 00 00 00 00 00 00
+80 80 80 80 80 80 80 80
+01 02 04 08 10 20 40 80
+00 FF 00 FF 00 FF 00 FF
+FF 00 FF 00 FF 00 FF 00
+```
 
 ## Troubleshooting
 

examples/peripherals/bitscrambler/main/CMakeLists.txt

@@ -1,6 +1,5 @@
-
 idf_component_register(SRCS "bitscrambler_example_main.c"
-                    PRIV_REQUIRES "esp_driver_bitscrambler"
-                    INCLUDE_DIRS ".")
+                       PRIV_REQUIRES "esp_driver_bitscrambler"
+                       INCLUDE_DIRS ".")
 
 target_bitscrambler_add_src("example.bsasm")

examples/peripherals/bitscrambler/main/bitscrambler_example_main.c

@@ -1,22 +1,17 @@
 /*
- * SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2023-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: CC0-1.0
  */
 
 #include <stdio.h>
 #include <string.h>
-#include <sys/unistd.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include "esp_err.h"
-#include "esp_log.h"
-#include "esp_check.h"
-#include <stdio.h>
-#include "driver/bitscrambler_loopback.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
+#include "esp_err.h"
+#include "esp_log.h"
 #include "esp_heap_caps.h"
+#include "driver/bitscrambler_loopback.h"
 
 //Assign a symbol to the example bitscrambler program. Note that the actual
 //assembly and including in the binary happens in the CMakeLists.txt file.

examples/peripherals/bitscrambler/main/example.bsasm

@@ -1,10 +1,13 @@
+# SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: Unlicense OR CC0-1.0
+
 # Example bitscrambler program. Reads in 8 bytes and spits out 8 bytes are
 # the 'rotated' version of the input bytes. Specifically, output byte 0
 # consists of bit 0 of input byte 0, bit 0 of input byte 1, bit 0 of input
 # byte 2 etc. Output byte 1 consists of bit 1 of input byte 0, bit 1 of
 # input byte 1, bit 1 of input byte 2, etc.
 
-cfg trailing_bytes 64			#If we have an EOF on the input, we still
+cfg trailing_bytes 8			#If we have an EOF on the input, we still
 								#need to process the 64 bits in M0/M1
 cfg prefetch true				#We expect M0/M1 to be filled
 cfg lut_width_bits 8			#Not really applicable here

examples/peripherals/bitscrambler/pytest_bitscrambler_loopback_example.py

@@ -0,0 +1,21 @@
+# SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
+# SPDX-License-Identifier: CC0-1.0
+import pytest
+from pytest_embedded import Dut
+
+
+@pytest.mark.esp32p4
+@pytest.mark.generic
+def test_bitscrambler_loopback_example(dut: Dut) -> None:
+    dut.expect_exact('BitScrambler example main', timeout=5)
+    dut.expect_exact('BitScrambler program complete. Input 40, output 40 bytes')
+
+    expected_lines = [
+        'FF 00 00 00 00 00 00 00',
+        '80 80 80 80 80 80 80 80',
+        '01 02 04 08 10 20 40 80',
+        '00 FF 00 FF 00 FF 00 FF',
+        'FF 00 FF 00 FF 00 FF 00',
+    ]
+    for line in expected_lines:
+        dut.expect_exact(line)