Starburst

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Starburst
Status
Stable
menuconfig Applications->Starburst
Pinning yes (optional)
Ecmd no
Depends on DMX Storage PCA9685
Requires a PCA9685on the i2c bus
Code https://github.com/ethersex/ethersex/tree/master/services/starburst
A PCA9685PW (TSSOP-28 Package) soldered onto a breakout board

Starburst uses the DMX data stored in DMX Storage and transmits it using I2C to a PCA9685 PWM controller. The PCA9685 is best for driving other circuits like high power LED drivers. Starburst is part of the Ethersex Lighting Architecture.

Starburst vs. StellaLight

Starburst advantages:

  • just needs two pins (3 pins for stroboscope)
  • has 12-bit PWM, thus can apply the Stevens' power law
  • delegates PWM generation => no load on the AVR
  • saves program space

StellaLight advantages:

  • does not need an extra controller


Slave Address

Enter the I2C address of the PCA9685 in the menuconfig in decimal format. Here's how to calculate it:

Fill in the values for {A0-A5} according to your layout.

High: 1 Low: 0

The 7th bit has a fixed value (1)

This is a sample for A5=>5V ; {A4-A0}=>GND

fixed A5 A4 A3 A2 A1 A0
1 1 0 0 0 0 0

to decimal => 96

DMX layout

DMX 0 DMX 1 DMX 2 DMX 3 DMX 4 DMX 5 DMX 6 DMX 7 DMX 8
channel 1 channel 2 channel 3 channel 4 mode 1 mode 2 mode 3 mode 4 global strobo (optional)

Valid Values

channel n : 0-255

mode n : 0 (instant change) 1 (fade to target)

global strobo : 1-25 (results in 1hz - 25hz) - 0 => no strobo

Stroboscope support

If you want to use the output enable pin, tick

  [*] Strobo Effect

and add the pin to your hardware pinning file (in this case PORTA PIN0):

  PCA9685_OE(PA0)