Data may be changed without notice - Proprietary information of Yamar Electronics Ltd.

©2019-2022 Yamar Electronics Ltd.

11

DS-DMX250 R 0.80

www.yamar.com

Tel: +972-3-5445294 Fax: +972-3-5445279

-

Start of frame preamble length

- 64usec

-

Arbitration pattern length (For RDM Discovery only) - 336 usec.

-

Packet length

- 180usec

Figure 12 – Frame (Message) structure

3.3.2

Transmit flow

Upon detecting the DMX/RDM start of message on the HDI pin, the DMX250 initiates a new powerline frame

containing the DMX/RDM message data bytes. A DMX/RDM frame contains a single DMX/RDM message sent from

the DMX-controller.

3.3.3

Receive flow

Upon detecting a powerline frame, the frame is decoded back into the DMX/RDM original message and sent

sequentially to the DMX-controller through the HDO pin.

3.3.4

Auto Arbitration mode (RDM Discovery)

The Arbitration mode is used to prioritize messages over the powerline when the RDM discovery process is

activated by the DMX-controller. The arbitration mechanism is used to allow the message with higher priority

(lower arbitration ID) to gain access and transmit its message over the DC-BUS. When an RDM discovery response

message from an RDM slave is detected, the powerline frame will begin with an arbitration sequence to gain

access to the powerline. In case the arbitration has passed successfully, then the DMX250 will proceed with data

frame transmission, else, the DMX250 will abort the transmission and receive the message from another DMX250

device.

3.4

Carrier frequency settings

Users can define carrier frequency from 5MHz to 30MHz with a spacing of 100 kHz (A total of 251 selectable

carriers). The active carrier frequency selection is made either by setting FREQ_SEL[4:0] pins or by configuring

REG_2 (see ‎5.2). After a power-up or hard-reset event, the carrier frequency is set according to FREQ_SEL[4:0]

state (see Table 7). Then, the carrier frequency is updated according to either REG_2 configuration or

FREQ_SEL[4:0] changed status. The last action prevails.

Upon completion of configuration, the DMX250 will update its operating carrier frequency within 1msec. During

this 1msec period, the DMX250 is kept in Soft-reset and will not communicate with its DMX-controller nor detect

new frames (messages) from the powerline.

When setting multiple DMX250 networks to operate over a single powerline, it is recommended to select carrier

frequencies spaced more than 1.5MHz from each other.