Spartan-3E FPGA Industrial Micromodule
User Manual
Two suitable ways of shirt-circuiting the
paid pair are by means of a zero-ohm
0603 (1608 metric) chip resistor or a
solder blob.
FPGA User I/Os
A total of 110 FPGA user I/Os are available
on corresponding contacts of B2B connect-
ors J4 and J5 (see Appendix).
■
37 differential digital I/O pairs:
each pair is configurable as 2 single-en-
ded digital I/Os, corresponding to a
maximum of 74 single-ended digital
I/Os;
■
4 differential clock input pairs:
each pair is configurable as differential
digital I/O pair or 2 single-ended clock
inputs or 2 single-ended digital I/Os (or
combination thereof), corresponding to
from a maximum of 8 independent clock
inputs to a maximum of 8 independent
digital I/Os;
■
1 differential clock input pair:
the pair is configurable as differential
digital input pair or as 2 single-ended
clock inputs or 2 single-ended digital in-
puts (or combination thereof), corres-
ponding to from a maximum of 2 inde-
pendent clock inputs to a maximum of 2
independent digital inputs;
■
21 single-ended digital I/Os;
■
5 single-ended inputs.
Table 4 summarizes the maximum avail-
able FPGA user I/Os divided by supply
voltage.
type
VccIO
3.3 V
diff. I/O pairs
≤ 18
≤ 23
diff inputs
≤ 1
none
diff. clocks
≤ 4
≤ 1
s. e. I/Os
≤ 46
≤ 58
s. e. inputs
≤ 2
≤ 4
s. e. clocks
≤ 8
≤ 3
Table 4: maximum FPGA user I/Os by
supply voltage.
Differential Pairs
The micromodule has a total of 42 differ-
ential signal pairs routed pairwise with a
differential impedance of 100 ohm to adja-
cent connector pins. These lines can be
used for high speed signaling up to
666 Mbit/s per differential pair (see Xilinx
Application Note XAPP485).
User Button and LED
LED
The LED is lit when the U_LED line (pin
R10) is set high as detailed in the follow-
ing table.
Signal
FPGA pin
FPGA ball
U_LED
IO_L15P_2
(bank 2)
R10
Table 5: user led signal details.
Push Button
The push button is connected to the PB in-
put (pin V16). as detailed in the following
table.
Trenz Electronic GmbH
6
Figure 10: R103 pad pair (blue high-
light) for 2.5 V internal supply.
Figure 9: R102 pad pair (blue high-
light) for 3.3 V internal supply.
