
Virtex-4 QV FPGA Ceramic Packaging www.xilinx.com 11
UG496 (v1.1) June 8, 2012
Pin Definitions
GC (2) Input/Output
These lower capacitance clock pins connect to Global Clock Buffers. These
pins do not support LVDS outputs, and they become regular user I/Os when
not needed for clocks. For single-ended clock inputs, use P-side pins only.
LC (2) Input/Output These lower capacitance pins do not support LVDS outputs.
SMn Input/Output SM1 through SM7 input pins are reserved for future use but can be used
for I/O or other designated functions.
VREF Input/Output These are input threshold voltage pins. They become user I/Os when an
external threshold voltage is not needed (per bank).
VRN Input/Output This pin is for the DCI voltage reference resistor of N transistor (per bank,
to be pulled High with reference resistor).
VRP Input/Output This pin is for the DCI voltage reference resistor of P transistor (per bank,
to be pulled Low with reference resistor).
Dedicated Configuration Pins (1)
CCLK_0 Input/Output Configuration clock. Output and input in Master mode or Input in Slave
mode.
CS_B_0 Input In SelectMAP mode, this is the active-low Chip Select signal.
D_IN_0 Input In bit-serial modes, D_IN is the single-data input.
DONE_0 Input/Output
DONE is a bidirectional signal with an optional internal pull-up resistor. As
an output, this pin indicates completion of the configuration process. As an
input, a Low level on DONE can be configured to delay the start-up sequence.
DOUT_BUSY_0 Output
In SelectMAP mode, BUSY controls the rate at which configuration data is
loaded.
In bit-serial modes, DOUT gives preamble and configuration data to
down-stream devices in a daisy chain.
HSWAPEN Input Enable I/O pull-ups during configuration
INIT_B_0 Bidirectional
(open-drain)
When Low, this pin indicates that the configuration memory is being
cleared. When held Low, the start of configuration is delayed. During
configuration, a Low on this output indicates that a configuration data
error has occurred.
M0_0, M1_0, M2_0 Input Configuration mode selection
PROG_B_0 Input Active Low asynchronous reset to configuration logic. This pin has a
permanent weak pull-up resistor.
PWRDWN_B_0 Input
(unsupported)
Active Low power-down pin (unsupported). Driving this pin Low can
adversely affect device operation and configuration. PWRDWN_B is internally
pulled High, which is its default state. It does not require an external pull-up.
Do not connect this pin—leave floating.
RDWR_B_0 Input In SelectMAP mode, this is the active-low Write Enable signal.
TCK_0 Input Boundary-Scan Clock
TDI_0 Input Boundary-Scan Data Input
Table 1-3: Virtex-4 QPro FPGA Pin Definitions (Cont’d)
Pin Name Direction Description