LED7708 datasheet(30/53 Pages) STMICROELECTRONICS

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Recommended operating conditions

LED7708

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Doc ID 022698 Rev 1

8.5.3

Internal registers access

The LED7708 is capable of supporting different data formats to satisfy different application

needs. The control registers are accessed one at a time by using 16-bit read/write

operations, while the brightness registers can be loaded in sequence (16x16-bit) or in a

single shot (1x256-bit). An additional data format (1x192-bit) allows data flow optimization

when only 12 bits are used for brightness control. After the startup sequence, the 16x16-bit

data format is set by default. Figure 8 details the signal timing for a write operation to the

DEVCFGx registers. Table 12 summarizes the available operations:

Figure 8.

Timing diagram related to a DEVCFGx write operation

Table 12.

Internal register operations encoding

DCLK rising edges with LE=1

Operation

Data latch (BRTxx)

2-3

Global latch (BRTxx)

4-5

Write CHSEL

6-7

Read CHSTA

8-9

Write DEVCFGx(*)

10-11

Read DEVCFGx

(1)

The content of the shift register is loaded into DEVCFG0 or DEVCFG1 according to the DEST bit (the most

significant bit, common to both registers). The data bits are shifted in starting from the most significant one

(MSB first).

12-13

Write GSLAT

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