R
Spartan and Spartan-XL Families Field Programmable Gate Arrays
Pin Descriptions
There are three types of pins in the Spartan/XL devices:
Any user I/O can be configured to drive the Global
Set/Reset net GSR or the global three-state net GTS. See
Global Signals: GSR and GTS, page 20 for more informa-
tion.
•
•
•
Permanently dedicated pins
User I/O pins that can have special functions
Unrestricted user-programmable I/O pins.
Device pins for Spartan/XL devices are described in
Table 18.
Before and during configuration, all outputs not used for the
configuration process are 3-stated with the I/O pull-up resis-
tor network activated. After configuration, if an IOB is
unused it is configured as an input with the I/O pull-up resis-
tor network remaining activated.
Table 18: Pin Descriptions
I/O
During
Config.
I/O After
Config.
Pin Name
Pin Description
Permanently Dedicated Pins
V
X
X
Eight or more (depending on package) connections to the nominal +5V supply
voltage (+3.3V for Spartan-XL devices). All must be connected, and each must be
decoupled with a 0.01 –0.1 µF capacitor to Ground.
CC
GND
X
X
I
Eight or more (depending on package type) connections to Ground. All must be
connected.
CCLK
I or O
During configuration, Configuration Clock (CCLK) is an output in Master mode and
is an input in Slave mode. After configuration, CCLK has a weak pull-up resistor
and can be selected as the Readback Clock. There is no CCLK High or Low time
restriction on Spartan/XL devices, except during Readback. See Violating the
Maximum High and Low Time Specification for the Readback Clock, page 39
for an explanation of this exception.
DONE
I/O
O
DONE is a bidirectional signal with an optional internal pull-up resistor. As an
open-drain output, it indicates the completion of the configuration process. As an
input, a Low level on DONE can be configured to delay the global logic initialization
and the enabling of outputs.
The optional pull-up resistor is selected as an option in the program that creates
the configuration bitstream. The resistor is included by default.
PROGRAM
I
I
I
PROGRAM is an active Low input that forces the FPGA to clear its configuration
memory. It is used to initiate a configuration cycle. When PROGRAM goes High,
the FPGA finishes the current clear cycle and executes another complete clear
cycle, before it goes into a WAIT state and releases INIT.
The PROGRAM pin has a permanent weak pull-up, so it need not be externally
pulled up to VCC.
MODE
(Spartan)
X
The Mode input(s) are sampled after INIT goes High to determine the
configuration mode to be used.
M0, M1
(Spartan-XL)
During configuration, these pins have a weak pull-up resistor. For the most popular
configuration mode, Slave Serial, the mode pins can be left unconnected. For
Master Serial mode, connect the Mode/M0 pin directly to system ground.
62
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