LAB 2A: Sahil Mahendra Mangaonkar (Worked with: Akshaya Nidhi Bhati and Yash Budhe)

Code-for-Lab-2-Q4/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.13)
+include(pico_sdk_import.cmake)
+project(modified C CXX ASM)
+set(CMAKE_C_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
+pico_sdk_init()
+add_executable(pio_ws2812)
+
+# generate the header file into the source tree as it is included in the RP2040 datasheet
+pico_generate_pio_header(pio_ws2812 ${CMAKE_CURRENT_LIST_DIR}/ws2812.pio OUTPUT_DIR ${CMAKE_CURRENT_LIST_DIR}/generated)
+
+target_sources(pio_ws2812 PRIVATE ws2812.c)
+pico_enable_stdio_usb(pio_ws2812 1)
+pico_enable_stdio_uart(pio_ws2812 0)
+target_link_libraries(pio_ws2812 PRIVATE pico_stdlib hardware_pio)
+pico_add_extra_outputs(pio_ws2812)
+
+# add url via pico_set_program_url
+#example_auto_set_url(pio_ws2812)
+
+add_executable(pio_ws2812_parallel)
+
+pico_generate_pio_header(pio_ws2812_parallel ${CMAKE_CURRENT_LIST_DIR}/ws2812.pio OUTPUT_DIR ${CMAKE_CURRENT_LIST_DIR}/generated)
+
+target_sources(pio_ws2812_parallel PRIVATE ws2812_parallel.c)
+
+target_compile_definitions(pio_ws2812_parallel PRIVATE
+        PIN_DBG1=3)
+
+target_link_libraries(pio_ws2812_parallel PRIVATE pico_stdlib hardware_pio hardware_dma)
+pico_add_extra_outputs(pio_ws2812_parallel)
+
+# add url via pico_set_program_url
+#example_auto_set_url(pio_ws2812_parallel)
+
+# Additionally generate python and hex pioasm outputs for inclusion in the RP2040 datasheet
+add_custom_target(pio_ws2812_datasheet DEPENDS ${CMAKE_CURRENT_LIST_DIR}/generated/ws2812.py)
+add_custom_command(OUTPUT ${CMAKE_CURRENT_LIST_DIR}/generated/ws2812.py
+        DEPENDS ${CMAKE_CURRENT_LIST_DIR}/ws2812.pio
+        COMMAND Pioasm -o python ${CMAKE_CURRENT_LIST_DIR}/ws2812.pio ${CMAKE_CURRENT_LIST_DIR}/generated/ws2812.py
+        )
+add_dependencies(pio_ws2812 pio_ws2812_datasheet)

Code-for-Lab-2-Q4/generated/ws2812.pio.h

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+// -------------------------------------------------- //
+// This file is autogenerated by pioasm; do not edit! //
+// -------------------------------------------------- //
+
+#pragma once
+
+#if !PICO_NO_HARDWARE
+#include "hardware/pio.h"
+#endif
+
+// ------ //
+// ws2812 //
+// ------ //
+
+#define ws2812_wrap_target 0
+#define ws2812_wrap 3
+
+#define ws2812_T1 2
+#define ws2812_T2 5
+#define ws2812_T3 3
+
+static const uint16_t ws2812_program_instructions[] = {
+            //     .wrap_target
+    0x6221, //  0: out    x, 1            side 0 [2] 
+    0x1123, //  1: jmp    !x, 3           side 1 [1] 
+    0x1400, //  2: jmp    0               side 1 [4] 
+    0xa442, //  3: nop                    side 0 [4] 
+            //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program ws2812_program = {
+    .instructions = ws2812_program_instructions,
+    .length = 4,
+    .origin = -1,
+};
+
+static inline pio_sm_config ws2812_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + ws2812_wrap_target, offset + ws2812_wrap);
+    sm_config_set_sideset(&c, 1, false, false);
+    return c;
+}
+
+#include "hardware/clocks.h"
+static inline void ws2812_program_init(PIO pio, uint sm, uint offset, uint pin, float freq, bool rgbw) {
+    pio_gpio_init(pio, pin);
+    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
+    pio_sm_config c = ws2812_program_get_default_config(offset);
+    sm_config_set_sideset_pins(&c, pin);
+    sm_config_set_out_shift(&c, false, true, rgbw ? 32 : 24);
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+    int cycles_per_bit = ws2812_T1 + ws2812_T2 + ws2812_T3;
+    float div = clock_get_hz(clk_sys) / (freq * cycles_per_bit);
+    sm_config_set_clkdiv(&c, div);
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+}
+
+#endif
+
+// --------------- //
+// ws2812_parallel //
+// --------------- //
+
+#define ws2812_parallel_wrap_target 0
+#define ws2812_parallel_wrap 3
+
+#define ws2812_parallel_T1 2
+#define ws2812_parallel_T2 5
+#define ws2812_parallel_T3 3
+
+static const uint16_t ws2812_parallel_program_instructions[] = {
+            //     .wrap_target
+    0x6020, //  0: out    x, 32                      
+    0xa10b, //  1: mov    pins, !null            [1] 
+    0xa401, //  2: mov    pins, x                [4] 
+    0xa103, //  3: mov    pins, null             [1] 
+            //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program ws2812_parallel_program = {
+    .instructions = ws2812_parallel_program_instructions,
+    .length = 4,
+    .origin = -1,
+};
+
+static inline pio_sm_config ws2812_parallel_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + ws2812_parallel_wrap_target, offset + ws2812_parallel_wrap);
+    return c;
+}
+
+#include "hardware/clocks.h"
+static inline void ws2812_parallel_program_init(PIO pio, uint sm, uint offset, uint pin_base, uint pin_count, float freq) {
+    for(uint i=pin_base; i<pin_base+pin_count; i++) {
+        pio_gpio_init(pio, i);
+    }
+    pio_sm_set_consecutive_pindirs(pio, sm, pin_base, pin_count, true);
+    pio_sm_config c = ws2812_parallel_program_get_default_config(offset);
+    sm_config_set_out_shift(&c, true, true, 32);
+    sm_config_set_out_pins(&c, pin_base, pin_count);
+    sm_config_set_set_pins(&c, pin_base, pin_count);
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+    int cycles_per_bit = ws2812_parallel_T1 + ws2812_parallel_T2 + ws2812_parallel_T3;
+    float div = clock_get_hz(clk_sys) / (freq * cycles_per_bit);
+    sm_config_set_clkdiv(&c, div);
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+}
+
+#endif
+

Code-for-Lab-2-Q4/generated/ws2812.py

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+# -------------------------------------------------- #
+# This file is autogenerated by pioasm; do not edit! #
+# -------------------------------------------------- #
+
+import rp2
+from machine import Pin
+# ------ #
+# ws2812 #
+# ------ #
+
+ws2812_T1 = 2
+ws2812_T2 = 5
+ws2812_T3 = 3
+
+@rp2.asm_pio(sideset_init=pico.PIO.OUT_HIGH, out_init=pico.PIO.OUT_HIGH, out_shiftdir=1)
+def ws2812():
+    wrap_target()
+    label("0")
+    out(x, 1)               .side(0) [2]  # 0
+    jmp(not_x, "3")         .side(1) [1]  # 1
+    jmp("0")                .side(1) [4]  # 2
+    label("3")
+    nop()                   .side(0) [4]  # 3
+    wrap()
+
+
+
+# --------------- #
+# ws2812_parallel #
+# --------------- #
+
+ws2812_parallel_T1 = 2
+ws2812_parallel_T2 = 5
+ws2812_parallel_T3 = 3
+
+@rp2.asm_pio()
+def ws2812_parallel():
+    wrap_target()
+    out(x, 32)                            # 0
+    mov(pins, invert(null))          [1]  # 1
+    mov(pins, x)                     [4]  # 2
+    mov(pins, null)                  [1]  # 3
+    wrap()
+
+
+

Code-for-Lab-2-Q4/pico_sdk_import.cmake

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+# This is a copy of <PICO_SDK_PATH>/external/pico_sdk_import.cmake
+
+# This can be dropped into an external project to help locate this SDK
+# It should be include()ed prior to project()
+
+if (DEFINED ENV{PICO_SDK_PATH} AND (NOT PICO_SDK_PATH))
+    set(PICO_SDK_PATH $ENV{PICO_SDK_PATH})
+    message("Using PICO_SDK_PATH from environment ('${PICO_SDK_PATH}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT} AND (NOT PICO_SDK_FETCH_FROM_GIT))
+    set(PICO_SDK_FETCH_FROM_GIT $ENV{PICO_SDK_FETCH_FROM_GIT})
+    message("Using PICO_SDK_FETCH_FROM_GIT from environment ('${PICO_SDK_FETCH_FROM_GIT}')")
+endif ()
+
+if (DEFINED ENV{PICO_SDK_FETCH_FROM_GIT_PATH} AND (NOT PICO_SDK_FETCH_FROM_GIT_PATH))
+    set(PICO_SDK_FETCH_FROM_GIT_PATH $ENV{PICO_SDK_FETCH_FROM_GIT_PATH})
+    message("Using PICO_SDK_FETCH_FROM_GIT_PATH from environment ('${PICO_SDK_FETCH_FROM_GIT_PATH}')")
+endif ()
+
+set(PICO_SDK_PATH "${PICO_SDK_PATH}" CACHE PATH "Path to the Raspberry Pi Pico SDK")
+set(PICO_SDK_FETCH_FROM_GIT "${PICO_SDK_FETCH_FROM_GIT}" CACHE BOOL "Set to ON to fetch copy of SDK from git if not otherwise locatable")
+set(PICO_SDK_FETCH_FROM_GIT_PATH "${PICO_SDK_FETCH_FROM_GIT_PATH}" CACHE FILEPATH "location to download SDK")
+
+if (NOT PICO_SDK_PATH)
+    if (PICO_SDK_FETCH_FROM_GIT)
+        include(FetchContent)
+        set(FETCHCONTENT_BASE_DIR_SAVE ${FETCHCONTENT_BASE_DIR})
+        if (PICO_SDK_FETCH_FROM_GIT_PATH)
+            get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
+        endif ()
+        # GIT_SUBMODULES_RECURSE was added in 3.17
+        if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+                    GIT_SUBMODULES_RECURSE FALSE
+            )
+        else ()
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+            )
+        endif ()
+
+        if (NOT pico_sdk)
+            message("Downloading Raspberry Pi Pico SDK")
+            FetchContent_Populate(pico_sdk)
+            set(PICO_SDK_PATH ${pico_sdk_SOURCE_DIR})
+        endif ()
+        set(FETCHCONTENT_BASE_DIR ${FETCHCONTENT_BASE_DIR_SAVE})
+    else ()
+        message(FATAL_ERROR
+                "SDK location was not specified. Please set PICO_SDK_PATH or set PICO_SDK_FETCH_FROM_GIT to on to fetch from git."
+                )
+    endif ()
+endif ()
+
+get_filename_component(PICO_SDK_PATH "${PICO_SDK_PATH}" REALPATH BASE_DIR "${CMAKE_BINARY_DIR}")
+if (NOT EXISTS ${PICO_SDK_PATH})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' not found")
+endif ()
+
+set(PICO_SDK_INIT_CMAKE_FILE ${PICO_SDK_PATH}/pico_sdk_init.cmake)
+if (NOT EXISTS ${PICO_SDK_INIT_CMAKE_FILE})
+    message(FATAL_ERROR "Directory '${PICO_SDK_PATH}' does not appear to contain the Raspberry Pi Pico SDK")
+endif ()
+
+set(PICO_SDK_PATH ${PICO_SDK_PATH} CACHE PATH "Path to the Raspberry Pi Pico SDK" FORCE)
+
+include(${PICO_SDK_INIT_CMAKE_FILE})

Code-for-Lab-2-Q4/ws2812.c

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+/**
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "pico/stdlib.h"
+#include "hardware/pio.h"
+#include "hardware/clocks.h"
+#include "ws2812.pio.h"
+
+#define IS_RGBW true
+#define NUM_PIXELS 150
+
+#ifdef PICO_DEFAULT_WS2812_PIN
+#define WS2812_PIN PICO_DEFAULT_WS2812_PIN
+#else
+// default to pin 2 if the board doesn't have a default WS2812 pin defined
+#define WS2812_PIN 12
+#endif
+
+
+void set_neopixel_color(uint32_t color) { 
+    pio_sm_put_blocking(pio0, 0, color << 8u);      //Write a word of data in state machines's TX FIFO. Block if the TX FIFO is full.
+} 
+void blink(uint32_t color, int n){
+    //The LED will blink 4 times with respective color. 500ms on and 500ms off.
+    for (int j=1; j<n+1;j++){
+        printf("Blink cycle %d\n", j);
+        set_neopixel_color(color);
+        sleep_ms(500);
+        set_neopixel_color(0x000000);
+        sleep_ms(500);
+    }
+}
+int i;
+int main() {
+    stdio_init_all();       // Initialize all of present standard stdio types that are linked into binary 
+    printf("WS2812 Smoke Test, using pin %d", WS2812_PIN);      //Display which pin is used as WS2812_PIN
+
+    PIO pio = pio0;     //Chooses which PIO instance to be used from 2 available ones i.e. pio0 and pio1
+    int sm = 0;     //State machine is set to be 0
+    uint offset = pio_add_program(pio, &ws2812_program);       //Find allocation where there is enough space to store our program
+
+    ws2812_program_init(pio, sm, offset, WS2812_PIN, 800000, IS_RGBW);      //Instantiate an instance of driver program
+
+    int t = 0;
+    while (1) {
+        //Take a number as an input
+        printf("Enter any number\n");
+        scanf("%d", &i);  
+        printf("Number = %d\n",i);
+        sleep_ms(100);
+        // Adafruit QT Py have power pin by default set to zero. So we need to manually set it to 1. This does't apply to RPi pico as it automatically sets it to 1
+        const uint LED_PIN = 11;        //Defining neopixel power pin 
+        gpio_init(LED_PIN);     //Initializing GPIO pin
+        gpio_set_dir(LED_PIN, GPIO_OUT);        // Set the pin as output
+        gpio_put(LED_PIN, 1);       //Set the pin high
+        uint32_t color;
+        switch(i) {
+            case 1:
+                printf("Red LED will blink once\n");
+                blink(0x00FF00,i);
+                break;
+            case 2:
+                printf("Green LED will blink twice\n");
+                blink(0xFF0000,i);
+                break;
+            case 3:
+                printf("Blue LED will blink thrice\n");
+                blink(0x0000FF,i);
+                break;
+            default:
+                printf("Error\n");
+
+        }
+    }
+}