Sundance SMT338 - Manual (Page 6)

Version 1.5 Page 6 of 19 SMT338 User Manual
Figure 1 shows the block diagram of the SMT338 I/O module. The following section
describes the SMT338 from a user’s point of view. Reference is made to the different blocks
of Figure 1 in the next Figures.
1.1. Differential lines
Differential signalling is the mechanism of choice when long-distance connections
from a PC to the outside world or/and high bandwidth requirements need to be
satisfied.
The SMT338 provides the user with differential pairs connected to two on-board 50-
way headers on one end and to a Virtex FPGA on the other end to offer an extremely
flexible differential signalling solution.
With the ability to interface directly to RS422, RS485, Low Voltage Differential
Signalling (LVDS), and Bus LVDS (BLVDS) known as well under Multipoint LVDM
differential I/O standards, the SMT338 supports input, output and I/O signalling.
Point-to-point and multidrop transfers are achievable with up to 40 pairs for RS422,
RS485 at 32 Mbps or LVDS at 400Mbps.
Figure 2 describes the different types of transfer.
Figure 2: LVD Familly sets standard
LVDS for point-to-point(1) and
multidrop(2) connections.
(1)One driver and one receiver on the
line
(2)One driver and more than one
receiver on the line.
LVDM for multipoint buses.
More than one driver and one
receiver on the line