
frame[n] output
Process start
(hit “enable”
register)
frame[n+1] output
frame[n+1] output
frame[n+1] output
frame[n+2] output
V-sync
(interrupt)
V-sync
(no interrupt)
V-sync
(no interrupt)
V-sync
(interrupt)
Emulation
suspended
Emulation
suspend release
Time
CPU can change register value
(but not reflected to module function)
Register configuration
during emulation
suspend is updated
Architecture
1778
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Video Port Interface (VPIF)
35.2.10.1.1 Receiver (Channels 0 and 1)
The VPIF receives input data from an external video device. The input format is BT.656 or BT.1120. If the
emulation suspend comes from the CPU during image processing, the VPIF will first try to run at the end
of the present frame and then the VPIF will be stalled (see
(c)).
The VPIF should only have a software stop mode; the hardware stop mode is not supported. If the CPU
changes the register configuration during an emulation suspended period, the new configuration should be
validated at the first V-sync after the suspended period.
35.2.10.1.2 Transmitter (Channels 2 and 3)
The VPIF transmits output data to an external video device. Source data for this output data is stored in
SDRAM. The VPIF needs information about the start address of the source data stored in SDRAM. The
output format is BT.656 or BT.1120.
In this mode, any suspend function should not be activated because you would like to see a displayed
picture, taking usage of this signal into consideration. From a system’s stand point, the VPIF should act in
the following sequence if the emulation suspend signal is detected:
1. The VPIF continues processing at the end of the present frame.
2. If the present frame is finished, interrupt assertion is stalled.
3. At phase (b), during the active period of the emulation suspend signal, the VPIF continues reading the
same frame data from SDRAM (no register change is reflected to module performance during this
period).
4. After the CPU returns back to the normal state, the VPIF performs as usual. New register
configurations done during an emulation suspend period are reflected in the functional performance at
the first V-sync after deassertion of the suspend signal.
If the CPU changes the register configuration during an emulation suspended period, the new
configuration should be validated at the first V-sync after the suspended period. Functional performance of
this mode is shown in
Figure 35-13. Emulation Suspend Function on Channels 2 and 3 (Transmit)