Linear Technology DC2218A Demo Manual page 6

DEMO MANUAL DC2218A
PRE-PROGRAMMED PATTERNS
CONNECT POWER
LT3797 STARTUP
CHARGE PUMP LT3965 ON
LINDUINO STARTUP
PULL PWM OFF
PRESS RESET
INTERACTIVE
KNOB
PROGRAMMED IN EMBEDDED C++ AND PRE-LOADED ON DC2026C (LINDUINO ONE)
Figure 3. DC2218A Attached Linduino One Pre-Programmed Software Flow-Chart
S1 Pattern Select Position
0. Comet: A comet of light runs around the sixteen LEDs
changing PWM dimming brightness quickly increasing
and decreasing at rates that look like a ball of fire zipping
around the LEDs. The interactive potentiometer controls
the speed of the comet.
1. Wave: A wave of light from right to left and from left to
right changing PWM dimming brightness quickly increas-
ing and decreasing at rates that look like a wave running
from one side of the LEDs to the other. The interactive
potentiometer controls the speed of the wave.
2. Side-to-Side Steer: Center headlight LEDs stay on to
face directly forward while the right and left side LEDs
turn on with brightness proportional to the amount that
the steering wheel (interactive potentiometer) is turned.
3. High Beam Blank: While the low beam Is on 100%
brightness, the sections of the high beam turn OFF .
Although the blank spots would be controlled by a so-
phisticated camera detecting an object in front of a car
to determine which high beam LEDs to turn off or dim,
the section on DC2218A is controlled by turning the
interactive potentiometer.
6
STARTS WITH ALL LEDS OFF AND USES PUSH BUTTON START
WAIT FOR ALERT FLAG
SCM WRITES TO ALL CHANNELS
(PWM LOW)
WAIT FOR
PWM ON, CONNECT LED STRING
High Beam Blank
Side-to-Side Steer
MAIN
LOOP
Wave
Comet
– TURN LEDS OFF, 1 LED OPEN AND SHORT
START PUSH BUTTON
Blinking indicates ready to start.
LEDs are OFF, LT3965 SWITCHES are ON.
4
3
5
2
CHECK
ROTARY SWITCH
POSITION
1 6
0 7
4. Side Bend Steer: All sixteen LEDs adjust PWM dim-
ming duty cycle and brightness based upon the position
of the steering wheel (interactive potentiometer). This
pattern represents a light that bends around the side of
a car, projecting a turning headlight pattern that is linked
to the steering wheel.
5. PWM All 16: All sixteen LEDs have the same PWM
dimming and brightness level that is set by the interactive
potentiometer. They range from OFF to ON In increments
of 1/256 PWM dimming.
6. Fade Wave: Using the PWM dim WITH FADE commands,
a wave of light is created by fading the LED brightnesses
up and down. WITH FADE option uses the logarithmic fade
function of the LT3965 and allows the brightness to fade
from low to high or from high to low with a single I
command. This pattern has low bus traffic.
7. GUI: GRAPHICAL USER INTERFACE position setting –
Use this position when connecting to the GUI. See details
above for downloading and connecting to the GUI via the
USB cable connection of DC2026C.
Side Bend Steer
PWM All 16
Fade Wave
GUI
2
C bus
dc2218af