STV2050A datasheet(24/83 Pages) STMICROELECTRONICS

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STV2050A - TIMEBASES

the corresponding convergence correction value is defined by the Horizontal DAC phase

HDP[6:0] value in the DB register.

The following range for the horizontal DAC phase is allowed:

≤ HDP ≤ 2 × HGD

The timing of the DAC output leads the most if HDP is equal to zero.

Figure 11. Horizontal DAC Phase

5.3.2 Horizontal Width Adjustment

In order to fit the video pattern into the full visible area of the screen, the width of the pattern

may be adjusted. Horizontal width adjustment is done by changing the number of clock cycles

between the vertical grid lines during retrace and the visible grid. The timing for the corre-

sponding DAC values is changed accordingly. Refer to Section 7.2.1 "Horizontal Grid Adjust-

ment" on page 35.

5.3.3 Auto-Calibration of DACs

All the DACs of the STV2050A can be automatically calibrated. This feature ensures a high

matching stability in both time and temperature. The process involves the sequential calibra-

tion of 120 cells.

To ensure optimal results, each cell must be calibrated at least every 4 ms.

The duration of one cell calibration must be greater than 2us. This duration is controlled by the

internal “calibration clock”. The calibration clock is generated using a divider of the system

clock. (Refer to Section 5.1 "LINE LOCKED PLL AND SYSTEM CLOCK" on page 22). The di-

vision ratio is programmable via the ACL[1:0] bits in D8.

HGN

n-1

n-2

n-3

n+1 n+2 n+3

HGRID

HGD HGD

HDP

n-1

n-2

n+1

n+2

n+3 n+4

DAC

output

coil

current

STV2050A Datasheet(PDF) 24 Page - STMicroelectronics