R
Spartan and Spartan-XL FPGA Families Data Sheet
Table 18: Pin Descriptions (Continued)
I/O
During
Config.
I/O After
Config.
Pin Name
Pin Description
SGCK1 -
SGCK4
(Spartan)
Weak
Pull-up
(except
SGCK4
is DOUT)
I or I/O
Four Secondary Global inputs each drive a dedicated internal global net with short
delay and minimal skew. These internal global nets can also be driven from
internal logic. If not used to drive a global net, any of these pins is a
user-programmable I/O pin.
The SGCK1-SGCK4 pins provide the shortest path to the four Secondary Global
Buffers. Any input pad symbol connected directly to the input of a BUFGS symbol
is automatically placed on one of these pins.
GCK1 -
GCK8
(Spartan-XL)
Weak
Pull-up
(except
GCK6 is
DOUT)
I or I/O
Eight Global inputs each drive a dedicated internal global net with short delay and
minimal skew. These internal global nets can also be driven from internal logic. If
not used to drive a global net, any of these pins is a user-programmable I/O pin.
The GCK1-GCK8 pins provide the shortest path to the eight Global Low-Skew
Buffers. Any input pad symbol connected directly to the input of a BUFGLS symbol
is automatically placed on one of these pins.
CS1
(Spartan-XL)
I
I
I
I/O
I/O
I/O
During Express configuration, CS1 is used as a serial-enable signal for
daisy-chaining.
D0-D7
(Spartan-XL)
During Express configuration, these eight input pins receive configuration data.
After configuration, they are user-programmable I/O pins.
DIN
During Slave Serial or Master Serial configuration, DIN is the serial configuration
data input receiving data on the rising edge of CCLK. After configuration, DIN is a
user-programmable I/O pin.
DOUT
O
I/O
During Slave Serial or Master Serial configuration, DOUT is the serial
configuration data output that can drive the DIN of daisy-chained slave FPGAs.
DOUT data changes on the falling edge of CCLK, one-and-a-half CCLK periods
after it was received at the DIN input.
In Spartan-XL family Express mode, DOUT is the status output that can drive the
CS1 of daisy-chained FPGAs, to enable and disable downstream devices.
After configuration, DOUT is a user-programmable I/O pin.
Unrestricted User-Programmable I/O Pins
I/O
Weak
Pull-up
I/O
These pins can be configured to be input and/or output after configuration is
completed. Before configuration is completed, these pins have an internal
high-value pull-up resistor network that defines the logic level as High.
64
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DS060 (v1.8) June 26, 2008
Product Specification
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