Time to try using the Arduino-Pico library to program the RPi Pico using the Arduino IDE.
I thought it would be good to try the NeoPixel Ring that I had previously tested using MicroPython Happy Pico Pi Day .
But first I am going to use one of the included examples to verify that I got the installation correct. I am using the TalkingToMyself example that uses both I2C interfaces, have one master and one slave and send data both ways between them.
Pretty simple test. The master just sends a string "pass #" with # incrementing each iteration and the slave responds with an incrementing hex number.
TalkingToMyself.ino
// Simple I2C master and slave demo - Earle F. Philhower, III
// Released into the public domain
//
// Using both onboard I2C interfaces, have one master and one slave
// and send data both ways between them
//
// To run, connect GPIO0 to GPIO2, GPIO1 to GPIO3 on a single Pico
#include <Wire.h>
void setup() {
Serial.begin(115200);
delay(5000);
Wire.begin();
Wire1.begin(0x30);
Wire1.onReceive(recv);
Wire1.onRequest(req);
}
static char buff[100];
void loop() {
static int p;
char b[90];
// Write a value over I2C to the slave
Serial.println("Sending...");
Wire.beginTransmission(0x30);
sprintf(b, "pass %d", p++);
Wire.write(b, strlen(b));
Wire.endTransmission();
// Ensure the slave processing is done and print it out
delay(1000);
Serial.printf("buff: '%s'\r\n", buff);
// Read from the slave and print out
Wire.requestFrom(0x30, 6);
Serial.print("\nrecv: '");
while(Wire.available()) {
Serial.print((char)Wire.read());
}
Serial.println("'");
delay(1000);
}
// These are called in an **INTERRUPT CONTEXT** which means NO serial port
// access (i.e. Serial.print is illegal) and no memory allocations, etc.
// Called when the I2C slave gets written to
void recv(int len) {
int i;
// Just stuff the sent bytes into a global the main routine can pick up and use
for (i=0; i<len; i++) buff[i] = Wire1.read();
buff[i] = 0;
}
// Called when the I2C slave is read from
void req() {
static int ctr = 765;
char buff[7];
// Return a simple incrementing hex value
sprintf(buff, "%06X", (ctr++) % 65535);
Wire1.write(buff, 6);
}
And it all works as expected.
I also tried the Fade example that fades the onboard LED. And that worked too.
Now to try the NeoPixel library from Adafruit. Unfortunately, this was a failure. It compiled and uploaded, but the nothing happened with the NeoPixel ring. I put a scope probe on the output pin and it never toggled. I suspect there is some definition missing in the library required to set up the NeoPixel timing for the RP2040. I'm sure that Adafruit will get this working...
I saw a video clip from Adafruit on Tom's Hardware that showed their new QT Py 2040 running with a SSD1306 I2C OLED display using the Arduino-Pico library https://youtu.be/sfC1msqXX0I . I tried the GFX demo for the SSD1306, but that gave me a compile failure.
I was surprised that I was getting a SPI related error when I was attempting to use I2C, but I couldn't figure how to make it go away.
I decided to try a simpler graphics library the u8g2/u8x8lib. I modified an example to display the internal RP2040 temperature and that worked.
Rpi_Pico_ReadTemp_OLED.ino
#include "hardware/adc.h"
#include <U8x8lib.h>
#include <Wire.h>
int val;
U8X8_SSD1306_128X64_NONAME_HW_I2C u8x8(/* reset=*/ U8X8_PIN_NONE);
void setup() {
u8x8.begin();
u8x8.setFont(u8x8_font_chroma48medium8_r);//Small Font 16 Characters
u8x8.noInverse();//Normal
u8x8.clear();
u8x8.setCursor(5,2);
u8x8.print("RPi Pico");
u8x8.setCursor(1,4);
u8x8.print("Temp = ");
}
void loop() {
delay(500);
u8x8.setCursor(9,4);// position, line# )
u8x8.print(" ");// clear value
u8x8.setCursor(9,4);// position, line# )
u8x8.print(analogReadTemp());// Write to lcd
u8x8.setCursor(15,4);
u8x8.print("C");
}
At this point it occurred to me that I hadn't checked to see if the Adafruit_SSD1306 and Adafruit_GFX libraries were up to date - they weren't. Unfortunately, I still had the compile issue. Then I realized that I also needed to update the Adafruit_BusIO library - and that fixed it. So, here is the working GFX demo - one caveat - my display is at address 0x3C rather than the standard 0x3D.
RPi_Pico_ssd1306_128x64_i2c.ino
/**************************************************************************
This is an example for our Monochrome OLEDs based on SSD1306 drivers
Pick one up today in the adafruit shop!
------> http://www.adafruit.com/category/63_98
This example is for a 128x64 pixel display using I2C to communicate
3 pins are required to interface (two I2C and one reset).
Adafruit invests time and resources providing this open
source code, please support Adafruit and open-source
hardware by purchasing products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries,
with contributions from the open source community.
BSD license, check license.txt for more information
All text above, and the splash screen below must be
included in any redistribution.
**************************************************************************/
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
// The pins for I2C are defined by the Wire-library.
// On an arduino UNO: A4(SDA), A5(SCL)
// On an arduino MEGA 2560: 20(SDA), 21(SCL)
// On an arduino LEONARDO: 2(SDA), 3(SCL), ...
#define OLED_RESET 4 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
#define NUMFLAKES 10 // Number of snowflakes in the animation example
#define LOGO_HEIGHT 16
#define LOGO_WIDTH 16
static const unsigned char PROGMEM logo_bmp[] =
{ B00000000, B11000000,
B00000001, B11000000,
B00000001, B11000000,
B00000011, B11100000,
B11110011, B11100000,
B11111110, B11111000,
B01111110, B11111111,
B00110011, B10011111,
B00011111, B11111100,
B00001101, B01110000,
B00011011, B10100000,
B00111111, B11100000,
B00111111, B11110000,
B01111100, B11110000,
B01110000, B01110000,
B00000000, B00110000 };
void setup() {
Serial.begin(9600);
// SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
Serial.println(F("SSD1306 allocation failed"));
for(;;); // Don't proceed, loop forever
}
// Show initial display buffer contents on the screen --
// the library initializes this with an Adafruit splash screen.
display.display();
delay(2000); // Pause for 2 seconds
// Clear the buffer
display.clearDisplay();
// Draw a single pixel in white
display.drawPixel(10, 10, SSD1306_WHITE);
// Show the display buffer on the screen. You MUST call display() after
// drawing commands to make them visible on screen!
display.display();
delay(2000);
// display.display() is NOT necessary after every single drawing command,
// unless that's what you want...rather, you can batch up a bunch of
// drawing operations and then update the screen all at once by calling
// display.display(). These examples demonstrate both approaches...
testdrawline(); // Draw many lines
testdrawrect(); // Draw rectangles (outlines)
testfillrect(); // Draw rectangles (filled)
testdrawcircle(); // Draw circles (outlines)
testfillcircle(); // Draw circles (filled)
testdrawroundrect(); // Draw rounded rectangles (outlines)
testfillroundrect(); // Draw rounded rectangles (filled)
testdrawtriangle(); // Draw triangles (outlines)
testfilltriangle(); // Draw triangles (filled)
testdrawchar(); // Draw characters of the default font
testdrawstyles(); // Draw 'stylized' characters
testscrolltext(); // Draw scrolling text
testdrawbitmap(); // Draw a small bitmap image
// Invert and restore display, pausing in-between
display.invertDisplay(true);
delay(1000);
display.invertDisplay(false);
delay(1000);
testanimate(logo_bmp, LOGO_WIDTH, LOGO_HEIGHT); // Animate bitmaps
}
void loop() {
}
void testdrawline() {
int16_t i;
display.clearDisplay(); // Clear display buffer
for(i=0; i<display.width(); i+=4) {
display.drawLine(0, 0, i, display.height()-1, SSD1306_WHITE);
display.display(); // Update screen with each newly-drawn line
delay(1);
}
for(i=0; i<display.height(); i+=4) {
display.drawLine(0, 0, display.width()-1, i, SSD1306_WHITE);
display.display();
delay(1);
}
delay(250);
display.clearDisplay();
for(i=0; i<display.width(); i+=4) {
display.drawLine(0, display.height()-1, i, 0, SSD1306_WHITE);
display.display();
delay(1);
}
for(i=display.height()-1; i>=0; i-=4) {
display.drawLine(0, display.height()-1, display.width()-1, i, SSD1306_WHITE);
display.display();
delay(1);
}
delay(250);
display.clearDisplay();
for(i=display.width()-1; i>=0; i-=4) {
display.drawLine(display.width()-1, display.height()-1, i, 0, SSD1306_WHITE);
display.display();
delay(1);
}
for(i=display.height()-1; i>=0; i-=4) {
display.drawLine(display.width()-1, display.height()-1, 0, i, SSD1306_WHITE);
display.display();
delay(1);
}
delay(250);
display.clearDisplay();
for(i=0; i<display.height(); i+=4) {
display.drawLine(display.width()-1, 0, 0, i, SSD1306_WHITE);
display.display();
delay(1);
}
for(i=0; i<display.width(); i+=4) {
display.drawLine(display.width()-1, 0, i, display.height()-1, SSD1306_WHITE);
display.display();
delay(1);
}
delay(2000); // Pause for 2 seconds
}
void testdrawrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2; i+=2) {
display.drawRect(i, i, display.width()-2*i, display.height()-2*i, SSD1306_WHITE);
display.display(); // Update screen with each newly-drawn rectangle
delay(1);
}
delay(2000);
}
void testfillrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2; i+=3) {
// The INVERSE color is used so rectangles alternate white/black
display.fillRect(i, i, display.width()-i*2, display.height()-i*2, SSD1306_INVERSE);
display.display(); // Update screen with each newly-drawn rectangle
delay(1);
}
delay(2000);
}
void testdrawcircle(void) {
display.clearDisplay();
for(int16_t i=0; i<max(display.width(),display.height())/2; i+=2) {
display.drawCircle(display.width()/2, display.height()/2, i, SSD1306_WHITE);
display.display();
delay(1);
}
delay(2000);
}
void testfillcircle(void) {
display.clearDisplay();
for(int16_t i=max(display.width(),display.height())/2; i>0; i-=3) {
// The INVERSE color is used so circles alternate white/black
display.fillCircle(display.width() / 2, display.height() / 2, i, SSD1306_INVERSE);
display.display(); // Update screen with each newly-drawn circle
delay(1);
}
delay(2000);
}
void testdrawroundrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2-2; i+=2) {
display.drawRoundRect(i, i, display.width()-2*i, display.height()-2*i,
display.height()/4, SSD1306_WHITE);
display.display();
delay(1);
}
delay(2000);
}
void testfillroundrect(void) {
display.clearDisplay();
for(int16_t i=0; i<display.height()/2-2; i+=2) {
// The INVERSE color is used so round-rects alternate white/black
display.fillRoundRect(i, i, display.width()-2*i, display.height()-2*i,
display.height()/4, SSD1306_INVERSE);
display.display();
delay(1);
}
delay(2000);
}
void testdrawtriangle(void) {
display.clearDisplay();
for(int16_t i=0; i<max(display.width(),display.height())/2; i+=5) {
display.drawTriangle(
display.width()/2 , display.height()/2-i,
display.width()/2-i, display.height()/2+i,
display.width()/2+i, display.height()/2+i, SSD1306_WHITE);
display.display();
delay(1);
}
delay(2000);
}
void testfilltriangle(void) {
display.clearDisplay();
for(int16_t i=max(display.width(),display.height())/2; i>0; i-=5) {
// The INVERSE color is used so triangles alternate white/black
display.fillTriangle(
display.width()/2 , display.height()/2-i,
display.width()/2-i, display.height()/2+i,
display.width()/2+i, display.height()/2+i, SSD1306_INVERSE);
display.display();
delay(1);
}
delay(2000);
}
void testdrawchar(void) {
display.clearDisplay();
display.setTextSize(1); // Normal 1:1 pixel scale
display.setTextColor(SSD1306_WHITE); // Draw white text
display.setCursor(0, 0); // Start at top-left corner
display.cp437(true); // Use full 256 char 'Code Page 437' font
// Not all the characters will fit on the display. This is normal.
// Library will draw what it can and the rest will be clipped.
for(int16_t i=0; i<256; i++) {
if(i == '\n') display.write(' ');
else display.write(i);
}
display.display();
delay(2000);
}
void testdrawstyles(void) {
display.clearDisplay();
display.setTextSize(1); // Normal 1:1 pixel scale
display.setTextColor(SSD1306_WHITE); // Draw white text
display.setCursor(0,0); // Start at top-left corner
display.println(F("Hello, world!"));
display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // Draw 'inverse' text
display.println(3.141592);
display.setTextSize(2); // Draw 2X-scale text
display.setTextColor(SSD1306_WHITE);
display.print(F("0x")); display.println(0xDEADBEEF, HEX);
display.display();
delay(2000);
}
void testscrolltext(void) {
display.clearDisplay();
display.setTextSize(2); // Draw 2X-scale text
display.setTextColor(SSD1306_WHITE);
display.setCursor(10, 0);
display.println(F("scroll"));
display.display(); // Show initial text
delay(100);
// Scroll in various directions, pausing in-between:
display.startscrollright(0x00, 0x0F);
delay(2000);
display.stopscroll();
delay(1000);
display.startscrollleft(0x00, 0x0F);
delay(2000);
display.stopscroll();
delay(1000);
display.startscrolldiagright(0x00, 0x07);
delay(2000);
display.startscrolldiagleft(0x00, 0x07);
delay(2000);
display.stopscroll();
delay(1000);
}
void testdrawbitmap(void) {
display.clearDisplay();
display.drawBitmap(
(display.width() - LOGO_WIDTH ) / 2,
(display.height() - LOGO_HEIGHT) / 2,
logo_bmp, LOGO_WIDTH, LOGO_HEIGHT, 1);
display.display();
delay(1000);
}
#define XPOS 0 // Indexes into the 'icons' array in function below
#define YPOS 1
#define DELTAY 2
void testanimate(const uint8_t *bitmap, uint8_t w, uint8_t h) {
int8_t f, icons[NUMFLAKES][3];
// Initialize 'snowflake' positions
for(f=0; f< NUMFLAKES; f++) {
icons[f][XPOS] = random(1 - LOGO_WIDTH, display.width());
icons[f][YPOS] = -LOGO_HEIGHT;
icons[f][DELTAY] = random(1, 6);
Serial.print(F("x: "));
Serial.print(icons[f][XPOS], DEC);
Serial.print(F(" y: "));
Serial.print(icons[f][YPOS], DEC);
Serial.print(F(" dy: "));
Serial.println(icons[f][DELTAY], DEC);
}
for(;;) { // Loop forever...
display.clearDisplay(); // Clear the display buffer
// Draw each snowflake:
for(f=0; f< NUMFLAKES; f++) {
display.drawBitmap(icons[f][XPOS], icons[f][YPOS], bitmap, w, h, SSD1306_WHITE);
}
display.display(); // Show the display buffer on the screen
delay(200); // Pause for 1/10 second
// Then update coordinates of each flake...
for(f=0; f< NUMFLAKES; f++) {
icons[f][YPOS] += icons[f][DELTAY];
// If snowflake is off the bottom of the screen...
if (icons[f][YPOS] >= display.height()) {
// Reinitialize to a random position, just off the top
icons[f][XPOS] = random(1 - LOGO_WIDTH, display.width());
icons[f][YPOS] = -LOGO_HEIGHT;
icons[f][DELTAY] = random(1, 6);
}
}
}
}
So, that begged the question - is my NeoPixel library up-to-date? And it wasn't. Now my NeoPixel demo is working...
RPi_Pico_NeoPixel_strandtest.ino
// A basic everyday NeoPixel strip test program.
// NEOPIXEL BEST PRACTICES for most reliable operation:
// - Add 1000 uF CAPACITOR between NeoPixel strip's + and - connections.
// - MINIMIZE WIRING LENGTH between microcontroller board and first pixel.
// - NeoPixel strip's DATA-IN should pass through a 300-500 OHM RESISTOR.
// - AVOID connecting NeoPixels on a LIVE CIRCUIT. If you must, ALWAYS
// connect GROUND first, then +, then data.
// - When using a 3.3V microcontroller with a 5V-powered NeoPixel strip,
// a LOGIC-LEVEL CONVERTER on the data line is STRONGLY RECOMMENDED.
// (Skipping these may work OK on your workbench but can fail in the field)
#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
#include <avr/power.h> // Required for 16 MHz Adafruit Trinket
#endif
// Which pin on the Arduino is connected to the NeoPixels?
// On a Trinket or Gemma we suggest changing this to 1:
#define LED_PIN 6
// How many NeoPixels are attached to the Arduino?
#define LED_COUNT 16
// Declare our NeoPixel strip object:
Adafruit_NeoPixel strip(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);
// Argument 1 = Number of pixels in NeoPixel strip
// Argument 2 = Arduino pin number (most are valid)
// Argument 3 = Pixel type flags, add together as needed:
// NEO_KHZ800 800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
// NEO_KHZ400 400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
// NEO_GRB Pixels are wired for GRB bitstream (most NeoPixel products)
// NEO_RGB Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
// NEO_RGBW Pixels are wired for RGBW bitstream (NeoPixel RGBW products)
// setup() function -- runs once at startup --------------------------------
void setup() {
// These lines are specifically to support the Adafruit Trinket 5V 16 MHz.
// Any other board, you can remove this part (but no harm leaving it):
#if defined(__AVR_ATtiny85__) && (F_CPU == 16000000)
clock_prescale_set(clock_div_1);
#endif
// END of Trinket-specific code.
strip.begin(); // INITIALIZE NeoPixel strip object (REQUIRED)
strip.show(); // Turn OFF all pixels ASAP
strip.setBrightness(50); // Set BRIGHTNESS to about 1/5 (max = 255)
}
// loop() function -- runs repeatedly as long as board is on ---------------
void loop() {
// Fill along the length of the strip in various colors...
colorWipe(strip.Color(255, 0, 0), 50); // Red
colorWipe(strip.Color( 0, 255, 0), 50); // Green
colorWipe(strip.Color( 0, 0, 255), 50); // Blue
// Do a theater marquee effect in various colors...
theaterChase(strip.Color(127, 127, 127), 50); // White, half brightness
theaterChase(strip.Color(127, 0, 0), 50); // Red, half brightness
theaterChase(strip.Color( 0, 0, 127), 50); // Blue, half brightness
rainbow(10); // Flowing rainbow cycle along the whole strip
theaterChaseRainbow(50); // Rainbow-enhanced theaterChase variant
}
// Some functions of our own for creating animated effects -----------------
// Fill strip pixels one after another with a color. Strip is NOT cleared
// first; anything there will be covered pixel by pixel. Pass in color
// (as a single 'packed' 32-bit value, which you can get by calling
// strip.Color(red, green, blue) as shown in the loop() function above),
// and a delay time (in milliseconds) between pixels.
void colorWipe(uint32_t color, int wait) {
for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip...
strip.setPixelColor(i, color); // Set pixel's color (in RAM)
strip.show(); // Update strip to match
delay(wait); // Pause for a moment
}
}
// Theater-marquee-style chasing lights. Pass in a color (32-bit value,
// a la strip.Color(r,g,b) as mentioned above), and a delay time (in ms)
// between frames.
void theaterChase(uint32_t color, int wait) {
for(int a=0; a<10; a++) { // Repeat 10 times...
for(int b=0; b<3; b++) { // 'b' counts from 0 to 2...
strip.clear(); // Set all pixels in RAM to 0 (off)
// 'c' counts up from 'b' to end of strip in steps of 3...
for(int c=b; c<strip.numPixels(); c += 3) {
strip.setPixelColor(c, color); // Set pixel 'c' to value 'color'
}
strip.show(); // Update strip with new contents
delay(wait); // Pause for a moment
}
}
}
// Rainbow cycle along whole strip. Pass delay time (in ms) between frames.
void rainbow(int wait) {
// Hue of first pixel runs 5 complete loops through the color wheel.
// Color wheel has a range of 65536 but it's OK if we roll over, so
// just count from 0 to 5*65536. Adding 256 to firstPixelHue each time
// means we'll make 5*65536/256 = 1280 passes through this outer loop:
for(long firstPixelHue = 0; firstPixelHue < 5*65536; firstPixelHue += 256) {
for(int i=0; i<strip.numPixels(); i++) { // For each pixel in strip...
// Offset pixel hue by an amount to make one full revolution of the
// color wheel (range of 65536) along the length of the strip
// (strip.numPixels() steps):
int pixelHue = firstPixelHue + (i * 65536L / strip.numPixels());
// strip.ColorHSV() can take 1 or 3 arguments: a hue (0 to 65535) or
// optionally add saturation and value (brightness) (each 0 to 255).
// Here we're using just the single-argument hue variant. The result
// is passed through strip.gamma32() to provide 'truer' colors
// before assigning to each pixel:
strip.setPixelColor(i, strip.gamma32(strip.ColorHSV(pixelHue)));
}
strip.show(); // Update strip with new contents
delay(wait); // Pause for a moment
}
}
// Rainbow-enhanced theater marquee. Pass delay time (in ms) between frames.
void theaterChaseRainbow(int wait) {
int firstPixelHue = 0; // First pixel starts at red (hue 0)
for(int a=0; a<30; a++) { // Repeat 30 times...
for(int b=0; b<3; b++) { // 'b' counts from 0 to 2...
strip.clear(); // Set all pixels in RAM to 0 (off)
// 'c' counts up from 'b' to end of strip in increments of 3...
for(int c=b; c<strip.numPixels(); c += 3) {
// hue of pixel 'c' is offset by an amount to make one full
// revolution of the color wheel (range 65536) along the length
// of the strip (strip.numPixels() steps):
int hue = firstPixelHue + c * 65536L / strip.numPixels();
uint32_t color = strip.gamma32(strip.ColorHSV(hue)); // hue -> RGB
strip.setPixelColor(c, color); // Set pixel 'c' to value 'color'
}
strip.show(); // Update strip with new contents
delay(wait); // Pause for a moment
firstPixelHue += 65536 / 90; // One cycle of color wheel over 90 frames
}
}
}
So, I guess the moral of the story is that you should keep your libraries up to date. Of course, in some cases this will cause older programs not to compile.
The Arduino-Pico library appears to work well with the Arduino IDE. I should try the Mbed library next as that will allow using some of the more advanced features of the RP2040.
The Arduino IDE is like an old shoe. I guess I prefer easy in my old age 
.
And I can't wait to try out the Adafruit QT PY 2040...
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