STV9432TAP View Datasheet(PDF) - STMicroelectronics

Part Name

Description

MFG CO.

STV9432TAP

100MHz OSD FOR MONITOR INCLUDING BEAM CURRENTS, VIDEO TIMING ANALYZER AND PWMs

STMicroelectronics 

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STV9432TAP

9 - BEAM CURRENTS MEASUREMENT

9.1 - BEAM CURRENT MEASUREMENT REGISTERS

The Beam Current Measurement circuitry uses three A to D converters, sampled at fOSC frequency.

These three 8 bits registers read the values of the last Beam currents measurement, initiated by I2C com-

mand (see TIMG register).

RCI Register: Red Beam Current Input

4012

RCI7

RCI6

RCI5

RCII4

RCI3

RCI2

RCI1

RCI0

GCI Register: Green Beam Current Input

4013

GCI7

GCI6

GCI5

GCI4

GCI3

GCI2

GCI1

GCI0

BCI Register: Blue Beam Current Input

4014

BCI7

BCI6

BCI5

BCI4

BCI3

BCI2

BCI1

BCI0

9.2 - BEAM CURRENT MEASUREMENT TRIGGER

The Beam Currents Measurement is performed according to the setting of SBN and TIMG registers :

9.2.1 - SBN Register

This 8 bits register holds the ”sampling bloc” number. The sampling bloc is a set of 4 consecutive scan

lines, the first of which is used for sampling the video timings or Beam currents. The reset value of this

register is 0.

4015

SBN7

SBN6

SBN5

SBN4

SBN3

SBN2

SBN1

SBN0

9.2.2 - TIMG Register

4016

STM

NFR1

NFR0 ADCDLY3 ADCDLY2 ADCDLY1

0

SELECT

This 8 bits register holds the following parameters:

STM

: Start Measurement Bit. This bit has

to be forced to 1 by I2C to start the

measurement sequence, depending

on the measurement selection bit.

When measurement is completed

the IC will reset this bit to 0.

NFR

[1:0]

: NFR number of measurement

frames, 1 to 4 frames

ADCDLY : Cut-off Beam current ADC sampling

[3:0]

delay time: 0 to 15 x tOSC, by tOSC

steps

SELECT : Selection of Beam current measure-

ment (0) or Timing measurement (1)

When measurement is completed the IC will reset

this bit to 0. The reset value of this register is 0.

To initiate a Beam Currents Measurement cycle:

- program the Sampling Bloc Number in the SBN

Register,

- program the TIMG Register, with: ”SELECT”

bit = 0, ”ADCDLY” bits specify the sampling

time during HFly, ”STM” bit = 1 (Start Measure-

ment).

As soon as the measurement cycle is finished, the

”STM” bit is automatically reset by the device.

After a Beam Currents Measurement cycle, read-

ing a zero in STM bit of TIMG register means that

the measurement is completed and the MCU may

read the results in RCI, GCI, and BCI registers.

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