CMX7163 QAM Modem
CMX7163
7.4.8 Rx Mode
In Rx mode a frame sync must be detected, then data is supplied to the host through the Rx Data FIFO
and should be read in response to a Cmd Done IRQ/Rx Data FIFO IRQs (when configured). The
CMX7163 will continue decoding the input waveform until the host sets the mode bits to either Tx or Idle,
as required. Once initial timing is established, timing corrections can be derived from the data to track the
received signal. The Rx Tracking register allows selection of the tracking mode used to track the signal
level, I/Q dc offset and symbol timing of the input signal as required. Use of the automatic tracking modes
is recommended.
Data may be in variable size blocks and/or
may be processed irregularly by the host
note:
Rx_Process
Load Command FIFO with Rx data
command(s). Set Modem Control to Rx
and receive either framesync.
The Modem will start to look for
frame sync. The host should
ensure that any external
note:
If enabled ,
IRQ=FrameSync will
occur before
note:
hardware is also set into Rx
mode (if not automatically
controlled by the GPIO pins).
No
IRQ=DataRdy
IRQ =
DataRdy or Rx
FIFOLvl?
yes
Load Command FIFO
with further Rx data
command(s)
Load data from Rx FIFO
An
Further data is requested the device
will buffer data internally. Therefore
an internal data overflow can occur if
the Command FIFO is not written
promptly.
more data to
receive?
IRQ=DataRdy
may still be
pending at this
point
No
note:
note:
yes
Transmission
required?
No
Set Modem Control to Idle
note:
Yes
The Modem will drop into Idle
mode. The host should ensure
that any external hardware is also
set into Idle mode (if not
Goto Tx_Process
automatically controlled by the
GPIO pins).
note:
See Tx_Process Flow
Diagram
Goto Idle_Process
Figure 13 Host Rx Data Flow
2014 CML Microsystems Plc
Page 31
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