Receiver & controller reference design targets LEDs

The receiver functions mainly as a light controller and, alternately, as a sound generator. As a lighting device, the receiver obtains data from the DMX controller that manages the display of four high-bright LEDs using the Z51F0811 MCU’s PWM function. As a sound generator, the receiver activates a speaker that is connected to the MCU’s buzzer driver. The UART peripheral of the Z51F0811 MCU is used to connect the DMX512-A receiver to the DMX512-A controller. The source code file associated with this reference design, RD0015-SC01.zip, is available free from the Zilog website. This source code has been compiled using the Keil uVision4 development tool, which is available from Keil.

Using Zilog’s DMX512-A controller with Zilog’s Z51F3220 MCU provides an understanding of the DMX512-A protocol, including its theory of operation. This reference design operates in one of three modes: Local Mode, PC Mode and Demo Mode. In the Live Mode, five control potentiometers are used to set transmitted light levels for each related DMX channel; each potentiometer corresponds to a single DMX channel. A PC application is required in the PC Mode. This PC application has two main functions: the DMX controller function and the Write to EEPROM function. The former provides two methods of updating and transmitting light levels to a DMX Universe through the DMX512-A controller. In the Auto-Fade method, light levels are set through sliders. All values from the set light levels down to zero and from zero up to the set light levels are transmitted continuously when played. In the Real-Time method, light levels are transmitted each time a slider value changes. The Write to EEPROM function is used to download lighting sequences into the DMX512-A controller’s EEPROM. In the Demo Mode, stored light sequences in the DMX controller’s EEPROM are transmitted to a DMX Universe.

Suitable applications include dimmer light controls, changing colour light controls, moving light controls, light sequence controls and GOBO lighting devices.