demo of pico pio minimal initialization done in main instead of .pio file, includes CMakeLists.txt and instruction on how to generate a pico project

pio_minimal.txt

//
// pio_minimal.c
// demo for minimal pio
// pio initialize is in main
// you normally see pio init in .pio file
//

#include <stdio.h>
#include "pico/stdlib.h"
#include "hardware/pio.h"
#include "blink.pio.h"

int main(){
  PIO pio = pio0;
  uint32_t sm = 0;
  uint32_t offset = pio_add_program(pio, &blink_program);
  pio_gpio_init(pio, 12); // led on pin 12
  pio_sm_set_consecutive_pindirs(pio, sm, 12, 1, true);
  pio_sm_config c = blink_program_get_default_config(offset);
  // slow down clock to see led toggling
  // 5 is system clock
  // 2000 hz is about the slowest you can run pio
  sm_config_set_clkdiv(&c, clock_get_hz(5) / 2000);
  //sm_config_set_clkdiv(&c, 800000000);
  sm_config_set_set_pins(&c, 12, 1);
  pio_sm_init(pio, sm, offset, &c);
  pio_sm_set_enabled(pio, sm, true);
}

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;; filename: blink.pio
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

.program blink
.wrap_target
  set pins, 1
  nop [30]
  nop [30]
  nop [30]
  nop [30]
  set pins, 0
  nop [30]
  nop [30]
  nop [30]
  nop [30]
.wrap

#
# CMakeLists.txt
#
# generate new pico project
# cd pico/pico-project-generator
# export PICO_SDK_PATH=/home/sonny/pico/pico-sdk
# python3 pico_project.py --gui
#   set project name
#   set location of project
#   click checkbox for Library Options (PIO interface)
#
# to generate .uf2 for pico
# cd project_name
# cd build
#   add to CMakeLists.txt below add_executable
#   pico_generate_pio_header(pio_minimal ${CMAKE_CURRENT_LIST_DIR}/blink.pio)
#
# cmake ..
# make
# under build directory you will find .uf2 file
# 
# while holding boot button
#   ground run pin momentarily
#   let go of boot button
#
# on file manager you should have RP2 mounted
#   drag and drop the .uf2 from build directory of your project
#   

# Generated Cmake Pico project file

cmake_minimum_required(VERSION 3.13)

set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

# Initialise pico_sdk from installed location
# (note this can come from environment, CMake cache etc)
set(PICO_SDK_PATH "/home/sonny/pico/pico-sdk")

set(PICO_BOARD pico CACHE STRING "Board type")

# Pull in Raspberry Pi Pico SDK (must be before project)
include(pico_sdk_import.cmake)

if (PICO_SDK_VERSION_STRING VERSION_LESS "1.4.0")
  message(FATAL_ERROR "Raspberry Pi Pico SDK version 1.4.0 (or later) required. Your version is ${PICO_SDK_VERSION_STRING}")
endif()

project(pio_minimal C CXX ASM)

# Initialise the Raspberry Pi Pico SDK
pico_sdk_init()

# Add executable. Default name is the project name, version 0.1

add_executable(pio_minimal pio_minimal.c )
pico_generate_pio_header(pio_minimal ${CMAKE_CURRENT_LIST_DIR}/blink.pio)

pico_set_program_name(pio_minimal "pio_minimal")
pico_set_program_version(pio_minimal "0.1")

pico_enable_stdio_uart(pio_minimal 1)
pico_enable_stdio_usb(pio_minimal 0)

# Add the standard library to the build
target_link_libraries(pio_minimal
        pico_stdlib)

# Add the standard include files to the build
target_include_directories(pio_minimal PRIVATE
  ${CMAKE_CURRENT_LIST_DIR}
  ${CMAKE_CURRENT_LIST_DIR}/.. # for our common lwipopts or any other standard includes, if required
)

# Add any user requested libraries
target_link_libraries(pio_minimal 
        hardware_pio
        )

pico_add_extra_outputs(pio_minimal)

demo of pico pio minimal initialization done in main instead of .pio file, includes CMakeLists.txt and instruction on how to generate a pico project