I am using the standard test code for adafruit 1331 oled display 96x64. It is connected properly with SPI configuration.
IF on battery power, I get unusual behavior most of the time, and on usb, some of the time, with just the following changes to the test code:
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1331.h>
#include <SPI.h>
// You can use any (4 or) 5 pins
#define sclk 13
#define mosi 11
#define cs 9 //was 10
#define rst 7 // 9
#define dc 8 //8
float battInput = 0;
void loop()
{
battInput = (float)analogRead(A4)*5/1024; // Read the analog value
delay(1);
}My display gets out of sync, goes garbled, or vertically loses sync..
If I remove the (float) cast, and go with
battInput = analogRead(A4)*5/1024; //Read the analog valueI get no disruption to my display with this change, but the voltage reading is incorrect by about a volt. Assume 4.2v max, but it reads 3.04. I assume this behavior is because AnalogRead is an Integer function, so I need to read input first, store as int, then convert it to a float afterward to avoid this. But why can't I just cast it in the same code line and have it work without corrupting my display? What am I missing?
Has anyone experienced this behavior with casting to float from analogread, why do you think it's corrupting my display, and what is the best way to do this conversion from analog read to a float? I want to use the input for a lowpass filter, which I already have the math figured out for.
It compiled just fine with the cast.
Thanks!
Here's the whole demo code with my little snippet embedded. As you can see, like I said. Minimal change. I am not even outputting my own reading to the display yet and I am experiencing issues. Multiple boards, multiple displays (3 of them that work with other sketches just fine), all the same issues randomly with this casting. More often on battery power. Nano.
/***************************************************
This is a example sketch demonstrating the graphics
capabilities of the SSD1331 library for the 0.96"
16-bit Color OLED with SSD1331 driver chip
Pick one up today in the adafruit shop!
------> http://www.adafruit.com/products/684
These displays use SPI to communicate, 4 or 5 pins are required to
interface
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.
BSD license, all text above must be included in any redistribution
****************************************************/
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1331.h>
#include <SPI.h>
// You can use any (4 or) 5 pins
#define sclk 13
#define mosi 11
#define cs 9 //was 10
#define rst 7 // 9
#define dc 8 //8
// Color definitions
#define BLACK 0x0000
#define BLUE 0x001F
#define RED 0xF800
#define GREEN 0x07E0
#define CYAN 0x07FF
#define MAGENTA 0xF81F
#define YELLOW 0xFFE0
#define WHITE 0xFFFF
// Option 1: use any pins but a little slower
//Adafruit_SSD1331 display = Adafruit_SSD1331(cs, dc, mosi, sclk, rst);
// Option 2: must use the hardware SPI pins
// (for UNO thats sclk = 13 and sid = 11) and pin 10 must be
// an output. This is much faster - also required if you want
// to use the microSD card (see the image drawing example)
Adafruit_SSD1331 display = Adafruit_SSD1331(&SPI, cs, dc, rst);
float p = 3.1415926;
float battInput =0;
void setup(void) {
Serial.begin(9600);
Serial.print("hello!");
display.begin();
Serial.println("init");
uint16_t time = millis();
display.fillScreen(BLACK);
time = millis() - time;
Serial.println(time, DEC);
delay(500);
lcdTestPattern();
delay(1000);
display.fillScreen(BLACK);
display.setCursor(0,0);
display.print("Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur adipiscing ante sed nibh tincidunt feugiat. Maecenas enim massa");
delay(1000);
// tft print function!
tftPrintTest();
delay(2000);
//a single pixel
display.drawPixel(display.width()/2, display.height()/2, GREEN);
delay(500);
// line draw test
testlines(YELLOW);
delay(500);
// optimized lines
testfastlines(RED, BLUE);
delay(500);
testdrawrects(GREEN);
delay(1000);
testfillrects(YELLOW, MAGENTA);
delay(1000);
display.fillScreen(BLACK);
testfillcircles(10, BLUE);
testdrawcircles(10, WHITE);
delay(1000);
testroundrects();
delay(500);
testtriangles();
delay(500);
Serial.println("done");
delay(1000);
}
void loop() {
battInput = (float)analogRead(A4)*5/1024; // Read the analog value
delay(1);
}
void testlines(uint16_t color) {
display.fillScreen(BLACK);
for (int16_t x=0; x < display.width()-1; x+=6) {
display.drawLine(0, 0, x, display.height()-1, color);
}
for (int16_t y=0; y < display.height()-1; y+=6) {
display.drawLine(0, 0, display.width()-1, y, color);
}
display.fillScreen(BLACK);
for (int16_t x=0; x < display.width()-1; x+=6) {
display.drawLine(display.width()-1, 0, x, display.height()-1, color);
}
for (int16_t y=0; y < display.height()-1; y+=6) {
display.drawLine(display.width()-1, 0, 0, y, color);
}
// To avoid ESP8266 watchdog timer resets when not using the hardware SPI pins
delay(0);
display.fillScreen(BLACK);
for (int16_t x=0; x < display.width()-1; x+=6) {
display.drawLine(0, display.height()-1, x, 0, color);
}
for (int16_t y=0; y < display.height()-1; y+=6) {
display.drawLine(0, display.height()-1, display.width()-1, y, color);
}
display.fillScreen(BLACK);
for (int16_t x=0; x < display.width()-1; x+=6) {
display.drawLine(display.width()-1, display.height()-1, x, 0, color);
}
for (int16_t y=0; y < display.height()-1; y+=6) {
display.drawLine(display.width()-1, display.height()-1, 0, y, color);
}
}
void testdrawtext(char *text, uint16_t color) {
display.setTextSize(1);
display.setTextColor(WHITE);
display.setCursor(0,0);
for (uint8_t i=0; i < 168; i++) {
if (i == '\n') continue;
display.write(i);
if ((i > 0) && (i % 21 == 0))
display.println();
}
}
void testfastlines(uint16_t color1, uint16_t color2) {
display.fillScreen(BLACK);
for (int16_t y=0; y < display.height()-1; y+=5) {
display.drawFastHLine(0, y, display.width()-1, color1);
}
for (int16_t x=0; x < display.width()-1; x+=5) {
display.drawFastVLine(x, 0, display.height()-1, color2);
}
}
void testdrawrects(uint16_t color) {
display.fillScreen(BLACK);
for (int16_t x=0; x < display.height()-1; x+=6) {
display.drawRect((display.width()-1)/2 -x/2, (display.height()-1)/2 -x/2 , x, x, color);
}
}
void testfillrects(uint16_t color1, uint16_t color2) {
display.fillScreen(BLACK);
for (int16_t x=display.height()-1; x > 6; x-=6) {
display.fillRect((display.width()-1)/2 -x/2, (display.height()-1)/2 -x/2 , x, x, color1);
display.drawRect((display.width()-1)/2 -x/2, (display.height()-1)/2 -x/2 , x, x, color2);
}
}
void testfillcircles(uint8_t radius, uint16_t color) {
for (uint8_t x=radius; x < display.width()-1; x+=radius*2) {
for (uint8_t y=radius; y < display.height()-1; y+=radius*2) {
display.fillCircle(x, y, radius, color);
}
}
}
void testdrawcircles(uint8_t radius, uint16_t color) {
for (int16_t x=0; x < display.width()-1+radius; x+=radius*2) {
for (int16_t y=0; y < display.height()-1+radius; y+=radius*2) {
display.drawCircle(x, y, radius, color);
}
}
}
void testtriangles() {
display.fillScreen(BLACK);
int color = 0xF800;
int t;
int w = display.width()/2;
int x = display.height();
int y = 0;
int z = display.width();
for (t = 0 ; t <= 15; t+=1) {
display.drawTriangle(w, y, y, x, z, x, color);
x-=4;
y+=4;
z-=4;
color+=100;
}
}
void testroundrects() {
display.fillScreen(BLACK);
int color = 100;
int i;
int t;
for(t = 0 ; t <= 4; t+=1) {
int x = 0;
int y = 0;
int w = display.width();
int h = display.height();
for(i = 0 ; i <= 8; i+=1) {
display.drawRoundRect(x, y, w, h, 5, color);
x+=2;
y+=3;
w-=4;
h-=6;
color+=1100;
}
color+=100;
}
}
void tftPrintTest() {
display.fillScreen(BLACK);
display.setCursor(0, 5);
display.setTextColor(RED);
display.setTextSize(1);
display.println("Hello World!");
display.setTextColor(YELLOW, GREEN);
display.setTextSize(2);
display.print("Hello Wo");
display.setTextColor(BLUE);
display.setTextSize(3);
display.print(1234.567);
delay(1500);
display.setCursor(0, 5);
display.fillScreen(BLACK);
display.setTextColor(WHITE);
display.setTextSize(0);
display.println("Hello World!");
display.setTextSize(1);
display.setTextColor(GREEN);
display.print(p, 5);
display.println(" Want pi?");
display.print(8675309, HEX); // print 8,675,309 out in HEX!
display.print(" Print HEX");
display.setTextColor(WHITE);
display.println("Sketch has been");
display.println("running for: ");
display.setTextColor(MAGENTA);
display.print(millis() / 1000);
display.setTextColor(WHITE);
display.print(" seconds.");
}
void mediabuttons() {
// play
display.fillScreen(BLACK);
display.fillRoundRect(25, 10, 78, 60, 8, WHITE);
display.fillTriangle(42, 20, 42, 60, 90, 40, RED);
delay(500);
// pause
display.fillRoundRect(25, 90, 78, 60, 8, WHITE);
display.fillRoundRect(39, 98, 20, 45, 5, GREEN);
display.fillRoundRect(69, 98, 20, 45, 5, GREEN);
delay(500);
// play color
display.fillTriangle(42, 20, 42, 60, 90, 40, BLUE);
delay(50);
// pause color
display.fillRoundRect(39, 98, 20, 45, 5, RED);
display.fillRoundRect(69, 98, 20, 45, 5, RED);
// play color
display.fillTriangle(42, 20, 42, 60, 90, 40, GREEN);
}
/**************************************************************************/
/*!
@brief Renders a simple test pattern on the LCD
*/
/**************************************************************************/
void lcdTestPattern(void)
{
uint8_t w,h;
display.setAddrWindow(0, 0, 96, 64);
for (h = 0; h < 64; h++) {
for (w = 0; w < 96; w++) {
if (w > 83) {
display.writePixel(w, h, WHITE);
} else if (w > 71) {
display.writePixel(w, h, BLUE);
} else if (w > 59) {
display.writePixel(w, h, GREEN);
} else if (w > 47) {
display.writePixel(w, h, CYAN);
} else if (w > 35) {
display.writePixel(w, h, RED);
} else if (w > 23) {
display.writePixel(w, h, MAGENTA);
} else if (w > 11) {
display.writePixel(w, h, YELLOW);
} else {
display.writePixel(w, h, BLACK);
}
}
}
display.endWrite();
}