How to convert byte array to uint64_t for arduino led matrix
I saw this byte array in the uint64_t conversion on this website for drawing the letter A ;
I think this byte array to uint64_t conversion reduces the code size and saves the space for storing the arduino IC code as well.
Byte array:
const byte IMAGES[][8] = {
{
B00011000,
B00100100,
B01000010,
B01111110,
B01000010,
B01000010,
B01000010,
B00000000
}};
uint64_t array:
const uint64_t IMAGES[] = {
0x004242427e422418
};
How to convert above showing byte array in uint64_t by looking above image of matrix with matrix without any tool (s) like this website
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If it's a little endian
uint64_t IMAGE = 0;
for (int i = 0; i < (sizeof(byte) * 8); i++)
{
IMAGE += ((uint64_t) byteIMAGE[i] & 0xffL) << (8 * i);
}
If this is the big end
uint64_t IMAGE = 0;
for (int i = 0; i < (sizeof(byte) * 8); i++)
{
IMAGE = (IMAGE << 8) + (byteIMAGE[i] & 0xff);
}
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Hope this example helps you, the main conversion function is
void displayImage(uint64_t image)
// ARDUINO NANO
#include "LedControl.h"
LedControl lc = LedControl(4, 3, 2, 1);
const uint64_t IMAGES[] = {
0x6666667e66663c00, // A
0x3e66663e66663e00, // B
0x3c66060606663c00 // C
};
const int IMAGES_LEN = sizeof(IMAGES) / sizeof(uint64_t);
void setup() {
Serial.begin(9600);
lc.shutdown(0, false);
lc.setIntensity(0, 8);
lc.clearDisplay(0);
}
void loop() {
for (int i = 0; i < IMAGES_LEN; i++) {
displayImage(IMAGES[i]);
delay(1000);
}
}
void displayImage(uint64_t image) {
for (int i = 0; i < 8; i++) {
byte row = (image >> i * 8) & 0xFF;
Serial.println(row); // <- SHOW
for (int j = 0; j < 8; j++) {
lc.setLed(0, i, j, bitRead(row, j));
}
}
Serial.println("---");
}
0x8040201008040201
equally
B10000000, // 1
B01000000, // 2
B00100000, // 4
B00010000, // 8
B00001000, // 16
B00000100, // 32
B00000010, // 64
B00000001 // 128
in function i is row j - column and bitRead(x,n)
tells you that the LED at position (i, j) should be on or off
// ex. for the value 128 on a generic row
for (int j = 0; j < 8; j++) {
Serial.println( bitRead(128, j));
}
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