Sundance SMT356 - Manual (Page 15)

Version 2.1 Page 15 of 26 SMT356356 User Manual
The maximum sampling rate per ADC is 10MHz, which indicates that the maximum
SDB word rate would be 80MHz. The SMT356 module allows for the SDB word rate
to be set to either 50 or 100MHz as follows,
JP1 – position 4
OFF ON
SDB=100MHz SDB=50MHz
A lower word rate may be needed where the receiving device is not able to sustain
the faster transfer speed.
If the sampled data rate (number of channels enabled x sample rate) is in excess of
the SDB data rate (50 or 100MHz), then the module’s internal FIFO will fill up. When
the FIFO has become full, LED1 will illuminate but the module will still process data.
The LED will remain illuminated until a control word with bit D23 set is received. Note
that this bit needs to be cleared before proper operation can be resumed.
At a sample rate of 5MHz with all channels enabled, the standard 50MHz SDB data
rate is sufficient to operate without FIFO filling problems.
Notes:
The SDB bi-directional functionality is not supported on this module.
The ACK signal on the SDB connector is not used.
The user defined pin UD0 is not used, UD1 is driven high (when connected to
an SMT332, UD1 is the FIFO partial reset).
The write enable pin (WEN) is driven active (low) by the SMT356 when it is
transmitting data on the SDB.