User manual

BIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT0

One data byte

DIM01

DIM23

(Clock signal)

(Data)

DIM01

DIM23

(Clock signal)

(Data)

BYTE1

(Group D)

BYTE2

(Group C)

BYTE3

(Group B)

BYTE4

(Group A)

DIM4

(End of Frame)

EOF

One data frame

LSB MSB

BOF

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PWM Dimming Control

In the serial interface mode the LM3463 evaluation board accepts a data frame which consists of four data

bytes to control the on duty of the four groups of output channels via the terminal TP12 (DIM01). Every

data byte contains 8 bits in LSB (Least Significant Bit) first ordering and is clocked into the data buffer of

the LM3463 at every rising edge of clock signal at the terminal TP14 (DIM23). Every time a data frame is

clocked in to the LM3463 the terminal TP16 (DIM4) should be pulled low to generate a falling edge to

indicate an ‘End-Of-Frame (EOF)’. Figure 9 shows the typical waveform of a data frame and the

corresponding clock and EOF signals.

Figure 9. Typical waveforms of a complete data frame in the serial interface mode

SNVA642A–May 2012–Revised May 2013 AN-2255 LM3463 Evaluation Board

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