STLED524 datasheet(22/72 Pages) STMICROELECTRONICS

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Detailed description

STLED524

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DocID026217 Rev 1

4.5.3

Clock register

This register is used to set up clock signals.

CLKOUT = 0, CLKOUT pin does not provide any clock signal. It is permanently low

CLKOUT = 1, CLKOUT pin provides CLK signal

CLKIN = 0, clock signal from the internal oscillator is used for display timings

CLKIN = 1, clock signal from CLKIN pin is used for display timings

SYNCEN = 0, driver operation synchronization is disabled by an external signal connected

to SYNC pin

SYNCEN = 1, driver operation synchronization is enabled by an external signal connected

to SYNC pin

SYNCSEL = 0, driver operation is enabled when SYNC signal is low

SYNCSEL = 1, driver operation is enabled when SYNC signal is high

REFSEL = 0, external reference defined by RSET value is used for current mirrors

REFSEL = 1, internal reference is used for current mirrors

If the clock signal changes from internal to external, the external clock has to be provided, at

least TINTTOEXTCLK before than CLKIN bit is set to 1.

Figure 5. Internal to external clock transition

SYNC pin behavior

If the synchronization is enabled (SYNCEN = 1), SYNC pin is in inactive state (defined by

SYNCSEL bit) and the micro writes EN, DISP or SLPEN bits, but the corresponding

operation is delayed, until SYNC pin gets to the active state.

If the synchronization is disabled (SYNCEN = 0), the micro writes EN, DISP or SLPEN bits,

and the corresponding operation starts immediately.

Table 19. Clock register

Clock

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Add = 10h

REFSEL SYNCSEL SYNCEN

CLKIN

CLKOUT

Default

NTCLK

IEXTCLK (CLKIN pin)

CLKIN bit

TINTTOEXTLCLK

GIPG27021413139LM

STLED524 Datasheet(PDF) 22 Page - STMicroelectronics

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