AN4374 datasheet(7/25 Pages) STMICROELECTRONICS

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AN4374

First LED power-on

At the end of the above sequence a 16-bit word with global latch must be sent, see Figure 6.

Figure 6. Brightness register: last BRT word example

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The output switch enable has to be sent. 16 bits with SDI=1 on switch register have to

be sent to have all 16 outputs ON (see Table 2 and Figure 7 and Figure 8).

Table 2. Digital key summary-write switch

Number

#CLK rising edge when the LE is 1

Command description

11-2

Write switch (to turn on/off output

channels)

3-4

Brightness data latch

5-6

Brightness global latch

Write configuration register

Read configuration register

Start open error detection mode

Start short error detection mode

Start combined error detection mode

End error detection mode

Thermal error reading

Reserved

Clk

SDI

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

first bit

last bit

Brightness register : BRT output 0(*) = 0xFFFF – BRT outputs 15 to 1(*)= already defined

(BRT reg. output 0 = 0xFFFF)

(*) We are assuming that this is the last 16- bit data word in the 16 word data stream needed to load correctly the brightness register.

Global Latch

Key

AM16855v1

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