Thanks for all that contributed to this topic! I got a really nice fade in / fade out combining the information from this topic with the information from this site.
This is my test code:
//12-Bit PWM on PIN9 using direct access to Timer1
//Fade in and out an LED connected to that pin
#define LEDValue OCR1A
const int PWMMax = 4095;
// table generated using code from: http://jared.geek.nz/2013/feb/linear-led-pwm
const unsigned int cie[256] = {
0, 2, 4, 5, 7, 9, 11, 12, 14, 16, 18, 20, 21, 23, 25, 27,
28, 30, 32, 34, 36, 37, 39, 41, 43, 45, 47, 49, 52, 54, 56, 59,
61, 64, 66, 69, 72, 75, 77, 80, 83, 87, 90, 93, 96, 100, 103, 107,
111, 115, 118, 122, 126, 131, 135, 139, 144, 148, 153, 157, 162, 167, 172, 177,
182, 187, 193, 198, 204, 209, 215, 221, 227, 233, 239, 246, 252, 259, 265, 272,
279, 286, 293, 300, 308, 315, 323, 330, 338, 346, 354, 362, 371, 379, 388, 396,
405, 414, 423, 432, 442, 451, 461, 470, 480, 490, 501, 511, 521, 532, 543, 553,
564, 576, 587, 598, 610, 622, 634, 646, 658, 670, 683, 695, 708, 721, 734, 748,
761, 775, 788, 802, 816, 831, 845, 860, 874, 889, 904, 920, 935, 951, 966, 982,
999, 1015, 1031, 1048, 1065, 1082, 1099, 1116, 1134, 1152, 1170, 1188, 1206, 1224, 1243, 1262,
1281, 1300, 1320, 1339, 1359, 1379, 1399, 1420, 1440, 1461, 1482, 1503, 1525, 1546, 1568, 1590,
1612, 1635, 1657, 1680, 1703, 1726, 1750, 1774, 1797, 1822, 1846, 1870, 1895, 1920, 1945, 1971,
1996, 2022, 2048, 2074, 2101, 2128, 2155, 2182, 2209, 2237, 2265, 2293, 2321, 2350, 2378, 2407,
2437, 2466, 2496, 2526, 2556, 2587, 2617, 2648, 2679, 2711, 2743, 2774, 2807, 2839, 2872, 2905,
2938, 2971, 3005, 3039, 3073, 3107, 3142, 3177, 3212, 3248, 3283, 3319, 3356, 3392, 3429, 3466,
3503, 3541, 3578, 3617, 3655, 3694, 3732, 3772, 3811, 3851, 3891, 3931, 3972, 4012, 4054, 4095
};
void setup() {
pinMode(9, OUTPUT);
TCCR1A = (1 << COM1A1) | (1 << WGM11); // Enable Fast PWM on OC1A (Pin 9)
TCCR1B = (1 << WGM13) | (1 << WGM12) | (1 << CS10); // Mode 14 Fast PWM/ (TOP = ICR1), pre-scale = 1
ICR1 = PWMMax; //Set the TOP value for 12-bit PWM
LEDValue = 0; //Set the PWM output to full off.
}
void loop() {
cieFadeIn();
led(0);
delay(1000);
cieFadeOut();
delay(2000);
}
void cieFadeIn()
{
for(int i = 0; i <= 255; i++)
{
led(i);
delay(75);
}
}
void cieFadeOut()
{
for(int i = 255; i >= 0; i--)
{
led(i);
delay(75);
}
}
void led(int brightness)
{
LEDValue = cie[brightness];
}
)
) When I set a single value for the led, it is ok, it is bright and continuous. But when I try and use it in my project, where it needs to read a value from an ultrasonic sensor and map the distance to brightness, and THEN light the led accordingly, it ends up blinking the led, and not even at the correct brightness, it is really faint.
