Accelerator Series FPGAs: ACT 3 PCI-Compliant Family
An Array with n Rows and m Columns
0
1
2
3
4
5
c–1
c
c+1
m m+1 m+2 m+3
Columns
Rows
n+1
Channels
n+2
IO IO IO IO IO IO
Top I/Os
IO IO IO CLKM
n+1
n
IO IO BIN S
IO IO BIN S
IO IO BIN S
S
S
S
S
C
C
C
C
C
C
C
C
S
S
S
S
S
S
S
S
C
C
C
C
C
C
C
C
S
S
S
S
C
C
C
C
S
S
S
S
IO IO
n
IO IO
IO IO
n–1
•
•
•
n–1
•
•
•
2
2
IO IO
IO IO BIN S
Left I/Os
1
0
1
0
Right I/Os
Bottom I/Os
BIO IO IO IO IO IO
IO IO IO IO IO IO
Figure 1 • Generalized Floor Plan of ACT 3 Device
The I/O module output Y is used to bring pad signals into the
array or to feed the output register back into the array. This
allows the output register to be used in high-speed state
machine applications. Side I/O modules have a dedicated
output segment for Y extending into the routing channels
above and below (similar to logic modules). Top/Bottom I/O
modules have no dedicated output segment. Signals coming
into the chip from the top or bottom are routed using F-fuses
and LVTs (F-fuses and LVTs are explained in detail in the
routing section).
D00
D01
OUT
Y
D10
D11
S1
S0
I/O Pad Drivers
All pad drivers are capable of being tri-state. Each buffer
connects to an associated I/O module with four signals: OE
(Output Enable), IE (Input Enable), DataOut, and DataIn.
Special signals used only during programming and test also
connect to the pad drivers: OUTEN (global output enable),
INEN (global input enable), and SLEW (individual slew
selection). See Figure 5.
A1 B1
A0 B0
Figure 2 • C-Module Diagram
preset/clear network (IOPCL). Either preset or clear can be
selected individually on an I/O-module-by-I/O-module basis.
5