User guide

14–4 Chapter 14: Control Synchronizer MegaCore Function
Functional Description
Video and Image Processing Suite January 2013 Altera Corporation
User Guide
Stall Behavior and Error Recovery
The Control Synchronizer stalls for several cycles between packets. When the Control
Synchronizer enters a triggered state it stalls while it writes to the Avalon-MM Slave
ports of other MegaCore functions. If the slaves do not provide a “wait request”
signal, the stall lasts for no more than 50 clock cycles. Otherwise the stall is of
unknown length.
1 Clipper and scaler use the
wait_request signal.
Error Recovery
The Control Synchronizer MegaCore function processes all packets until an
endofpacket signal is received; the image width, height and interlaced fields of the
control data packets are not compared against the following video data packet. Any
mismatch of the
endofpacket signal and the frame size of a video data packet is
propagated unchanged to the next MegaCore function.
1 For more information about the stall behavior and error recovery, refer to “Stall
Behavior and Error Recovery” on page 1–3.
Latency
Table 14–2 lists the approximate latency from the video data input to the video data
output for typical usage modes of the Control Synchronizer MegaCore function. You
can use this table to predict the approximate latency between the input and the output
of your video processing pipeline.
The latency is described using one or more of the following measures:
■ the number of progressive frames
■ the number of interlaced fields
■ the number of lines when less than a field of latency
■ a small number of cycles O (cycles)
The latency is measured with the assumption that the MegaCore function is not being
stalled by other functions on the data path (the output ready signal is high).
Interlaced / Progressive Run-time controlled. Any valid value supported.
Bits per Color Sample Number of bits per color sample selected in the parameter editor.
Color Pattern
Up to four color planes in parallel, with any number of color planes in
sequence.
Table 14–1. Control Synchronizer Avalon-ST Video Protocol Parameters (Part 2 of 2)
Parameter Value
Table 14–2. Control Synchronizer Latency
Mode Latency
All modes O (cycles)
(1)
Note to Table 14–2:
(1) O refers to a small number of clock cycles, and is not of zero value.