Sundance SMT391-VP - Manual (Page 10)

Version 1.3 Page 10 of 41 SMT391-VP User Manual
SLB
The SMT391-VP is composed of the SMT391 module plugged on the base module
SMT338-VP. Both modules communicate via the SLB.
SDB
The SMT391-VP comes with two SHB connectors. A 32-bits SDB interface is
mapped on each of the SHB to output the data stored in the DDR SDRAM.
RSL
The SMT391-VP comes with 8 RSL that can carry the data stream coming from the
ADC at up to 1GB/s. RSL are used for real time applications.
Refer to RSL specification for a complete description.
Comport
The SMT391-VP provides two comports: comport 0 and comport 3. The comport 3 is
used to control the module.
The FPGA is configured at power-up over Comport 3. The configuration process is
controlled by a microprocessor (a Texas Instruments
MSP430 family microprocessor)
which shared the comport with the FPGA. Once the FPGA is configured the
configuration Comport is used for configuring control registers in the FPGA to control
the functions of the FPGA.
LED
Refer to the SMT338-VP user guide for the description of the LEDs.
External triggers
Two external triggers are available with the SMT391-VP. They are used to start the
acquisition of the analogue signal.
The external trigger input is received by a LVPECL input buffer on the SMT391. The
buffered signal is passed down as a differential LVPECL to the FPGA on the
SMT338-VP. For compatibility reasons with other daughter card modules there are
no ECL termination resistors mounted on the SMT338-VP. For this reason the pulse
width of the input trigger must be at least 1uS before the FPGA will register it.
As this might be a problem for some applications this issue has been resolved on the
newer SMT338-VP modules and appropriate termination resistors are provided to
improve the response time of the FPGA to an external trigger.
For most systems it is likely that there will be a system host (DSP Module). For this
reason it is also possible to send a software trigger to the SMT391-VP over Comport
3. There will however be latency from the time that the command is sent to the time
that data are acquired.