ST72754 datasheet(59/144 Pages) STMICROELECTRONICS

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ST72774/ST727754/ST72734

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SYNC PROCESSOR (SYNC) (Cont’d)

ClampOut and Moire Signal

Clamp Output signal

The clamping pulse generator can control the

pulse width and polarity signal and can be

configured as pseudo-front porch or back porch.

To use the ClampOut signal:

– Select the Clamping Pulse width:

BP0/BP1 bits in MCR register

– Program the Clamp polarity:

CLPINV bit in POLR register

– Select the ClampOut signal as back-porch (after

falling edge of HSYNCO) or pseudo-front porch

(after the rising edge of HSYNCO):

HS0/HS1 bits in MCR register.

– Enable the CLAMPOUT signal:

CLMPEN bit in ENR register

Moire Signal

The Moire output signal is available (instead of the

clamping signal) to reduce the screen Moire effect

and improve color transitions.

The CLAMPOUT pin is alternatively used to output

a Moire signal.

The output signal toggles at each HFBACK rising

edge. After each VFBACK falling edge, the value

of the Moire output is the opposite of the previous

one, independent of the number of HFBACK

pulses during the VFBACK low level.

To use the Moire signal:

– Select the Moire signal:

Reset the BP0/BP1 bits in MCR register

– Enable the output signal:

CLMPEN bit in ENR register

Figure 40. Clamping Pulse (CLAMPOUT) Delay

HSYNCO

CLAMPOUT

Maximum delay:

Programmable clamping width: 0, 167ns, 333ns, 666ns

(Fixed delay of 10 to 30ns) + (fOSC/2) = approx. 110ns.

ST72754 Datasheet(PDF) 59 Page - STMicroelectronics