Circuit Description
The BL-48 Illuminator circuitry is most easily described as six sections, which are the power
supply, the microcontroller, the DMX interface section, the address and mode selection section, the
DAC or PWM output section, and the LED drivers and array. The microcontroller is the key
element in the circuit, as the data ports on the device are assigned to all key circuit and interface
functions. The microcontroller responds to settings of the mode and address control switches, reads
incoming DMX data with the proper address information, and generates the output data which
controls the LED drivers. Each circuit section is explained in further detail below.
Circuit Block Diagram
Theory of Operation
Upon power up, the microcontroller sets the configuration of all internal registers and variables
according to firmware programming, then reads the settings of the internal mode jumpers to
determine the general display configuration. Once these settings are established, the controller then
reads the settings of the DMX address switches, and goes into either a manual display mode if the
address settings are 600 or higher, or a DMX controlled mode if the address settings are in the range
of from 1 to 512. If no DMX data is available, the unit enters a “Standby” state, prepared to
respond to valid DMX data input. The microcontroller monitors the DMX control lines, and awaits
a signal to initiate a display. Upon receipt of a suitable signals, the controller then sets the intensity
or other display variables to the to the required levels established by the DMX data. The display is
maintained at the last valid level for a preset interval of about 5 seconds if DMX data is lost or
interrupted. If no DMX data is received after this interval, the controller then returns to the normal
standby state, and continues to monitor the inputs for additional DMX control signals.
