No red LED lights up in apa102.c example program. #446
Description
When running the apa102.c example program on a LED board, the "wave" pattern works flawlessly, but the color red never lights up.
Upon further investigation of the code, I believe I found the following typo in the main function:
for (int i = 0; i < N_LEDS; ++i) {
put_rgb888(pio, sm,
wave_table[(i + t) % TABLE_SIZE],
wave_table[(2 * i + 3 * 2) % TABLE_SIZE],
wave_table[(3 * i + 4 * t) % TABLE_SIZE]
);
}
Should rather be:
for (int i = 0; i < N_LEDS; ++i) {
put_rgb888(pio, sm,
wave_table[(i + t) % TABLE_SIZE],
wave_table[(2 * i + 3 * t) % TABLE_SIZE],
wave_table[(3 * i + 4 * t) % TABLE_SIZE]
);
}
For clarity, in the second wave_table[] access, the current code uses constant 2, rather than the likely intended variable t.
Testing proves to fix the issue.