STV2050A datasheet(60/83 Pages) STMICROELECTRONICS

60 / 83 page

60/83

STV2050A - OPTICAL LOOP

12.2.1 OPTT Pin used as an Input

The status of OPTT is available in S05 in register E5.

12.2.2 OPTT Pin used as an Output

The OPTT output can either be forced to the electrical “1” level, or can be programmed in the

same way as the auto-alignment pattern. This is carried out by the OOS bit in the E5 register.

In the latter case, the timing of the OPPT signal typically overlaps the auto-alignment pattern.

The final signal is used to control the OPTI and OPTT port functions. The timing for the signal

is defined by the ED and EE registers.

Offset values larger than one grid distance or invalid vertical grid numbers for start or stop po-

sition will cause unexpected results at the OPTT_PATTERN signal.

The OPTT_PATTERN signal is not influenced by the horizontal or vertical blanking function.

12.3 OPTI SENSOR STATUS PORT

The level applied to the OPTI pin can be read using the S11 bit in the E5 register.

The OPTI level can be ANDed with the window defined on the OPTT using the OPI in the E5

S05

0: < 0.7 V on OPTT

1: > 2.6 V on OPTT

OOS

0: Data output = the ODT bit in the E5 register

1: Programmable timing

HG3

Grid number of horizontal start

HO3

Offset of horizontal start (number of clock cycles, 1 grid max.)

HG4

Grid number of horizontal end

HO4

Offset of horizontal end (number of clock cycles, 1 grid max.)

VG3

Grid number of vertical start

VO3

Offset of vertical start (number of video lines, 1 grid max.)

VG4

Grid number of vertical end

VO4

Offset of vertical end (number of video lines, 1 grid max.)

OPI

0: S11 = OPTI AND window

1: No windowing

STV2050A Datasheet(PDF) 60 Page - STMicroelectronics