Firmware Description
3.3 Standalone Mode
When the LED box is powered up with SW1 being pressed, it enters standalone mode. When compared to the PC control mode, this standalone mode can act as a quick and simple demo that does not require a host PC. The control of the LED light box can be done through the onboard buttons. However, the PC control mode can have more control on the PWM output.
The functions of the buttons are as follows:
•SW6 (IRQ): Demonstration Display Enable/Disable
If SW6 is pressed, the LED box enters the demonstration display state where certain preset colors display sequentially with some other lighting effects. The demonstration mode can be exit by pressing SW6 again.
•SW1: Preset Colors Toggle
Whenever SW1 has been pressed and released, the LED box toggles to another preset color. The LED1 lights up while LED2 turns off.
•SW2: Auto White Balance Control
If SW2 has been pressed, the LED box turns to auto white balance state and give a white color. The small on board LED2 lights up while LED1 turns off, indicating an auto white balance state. There are two preset white color with different color temperatures available for selection. To swap between different preset color temperatures, press the SW2 button once more. The auto white balance state can be turn off by pressing SW1.
•SW3: Decrease Brightness
The output brightness increases if SW3 has been pressed.
•SW4: Increase Brightness
The output brightness decreases if SW4 has been pressed.
•SW1+SW2: PWM Frequency Selection
The Output PWM Frequency can be changed with following steps:
1.Press and hold SW1
2.Press SW2
3.Release SW2
4.Release SW1
After performing the above action, the output PWM frequency can be changed. There are three preset settings available, 30 Hz, 120 Hz, and 600 Hz. For examples, after changing from 30 Hz to 120 Hz using above steps, it can set the PWM to 600 Hz by applying the above steps again.
NOTE
The output brightness is changed after changing the frequency. As the PWM output values remain the same, a change in PWM frequency modifies the PWM duty as well.
The PWM frequency selection steps above are invalid if the LED box is running at demonstration display state. In addition, the PWM frequency is changed to the default value of 120 Hz after the demonstration display state has been exited by pressing SW6.
LED Lighting Control using the MC9S08AW60, Rev. 1
26 | Freescale Semiconductor |
