4 real-time polling, Polling – Texas Instruments TVP5154EVM User Manual
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8.4
Real-Time Polling
WinVCC in Depth
The I
2
C system test can be run at anytime by clicking Run System I
2
C Test in the Tools menu.
Figure 11. I
2
C System Failure
Real-time polling provides polling functions that execute continuously in the background, when enabled via
the Real-Time Polling dialog. There are two polling functions. The function that applies to the TVP5154 is
VIDEO-STANDARD AUTO-SWITCH POLLING.
When the TVP5154 detects a change in the input video standard, it automatically switches to operation in
the detected standard (which includes all necessary I
2
C register initialization) for proper decoding of the
input video. To enable auto-switch on the TVP5154, the Set Video Standard register must be set to
auto-switch mode (Reg 0x28 = 0x00).
If the WinVCC auto-switch polling function is enabled, the detected video standard status from the
TVP5154 is polled until a change in the input video standard (or in the TVP5154 sampling mode) is
detected. When a change is detected, the video encoder is reprogrammed as needed for the detected
standard. Using this feature, the video source can change its video standard and the system displays
using the new standard, without user intervention.
When using the TVP5154 EVM with the DM642 and a composite output from the 7311 encoder, it is
required to disable auto-switch polling by clicking on the ENABLED button in the Real-Time Polling dialog
box as shown in
The real-time polling dialog can also be accessed once WinVCC is up and running by clicking Real-Time
Polling in the Tools menu.
SLEU069A – February 2006 – Revised July 2006
TVP5154EVM User's Guide
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