Sundance SMT8121 - Manual (Page 20)

One copy is sent to the storage task which captures a snapshot of the samples and
sends them to the “main” task for display and FFT processing. This is a non real
time loop.
The other copy is sent to task “split” which separates the samples coming on its
input channel on two output channels each having four samples. Each output
channel is mapped onto one SDB link linking the SMT368 to the SMT368A. Each
SDB runs at 1/8
th the sampling frequency producing a data rate of 500MB/s.
On the SMT368A the samples are received by tasks “unsplit” which merges the data
arriving on its two input ports onto one output port.
The samples are then packed on 2 samples at a time and accelerated to 500MHz by
the task “pack64to16”.
Because the samples coming from the SMT391 are 8-bits and the DAC of the
SMT381 expects 14-bits samples, the task “scaler” multiplies each sample by a
constant value.
The samples are finally sent to task DAC381 which forwards them to the DAC on
the SMT381.
8.3 Building the example
Make sure that you have Xilinx ISE9.2sp4 as well as Diamond V3.1.10 or later
installed on your PC.
In the Diamond IDE, press CNTRL+B to build the application.
When using Diamond in command line, run the MAKE in directory
“com.sundance.example.smt8121\export” or
“com.sundance.example.smt8121.sa\export”.
8.4 Resource usage
The resource usage for the FPGA of the SMT391 is as follow:
BUFG DCM RAM16 SLICES
8 out of 32 1 out of 8 44 out of 192 2267 out of 15360
25% 12% 22% 14%
The resource usage for the FPGA of the SMT381 is as follow:
BUFG DCM RAM16 SLICES
8 out of 32 1 out of 8 16 out of 192 1998 out of 15360
25% 12% 8% 13%
Application Note SMT8121 Page 20 of 26 Last Edited: 19/02/2009 16:32:00