DS031 Datasheet, PDF (45/318 Pages) Xilinx, Inc – Summary of Features

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Virtex-II Platform FPGAs: Functional Description
Virtex-II FPGA device. Timing is similar to the Slave Serial-
MAP mode except that CCLK is supplied by the Virtex-II
FPGA.
Boundary-Scan (JTAG, IEEE 1532) Mode
In Boundary-Scan mode, dedicated pins are used for con-
figuring the Virtex-II device. The configuration is done
entirely through the IEEE 1149.1 Test Access Port (TAP).
Virtex-II device configuration using Boundary-Scan is com-
patible with the IEEE 1149.1-1993 standard and the new
IEEE 1532 standard for In-System Configurable (ISC)
devices. The IEEE 1532 standard is backward compliant
with the IEEE 1149.1-1993 TAP and state machine. The
IEEE Standard 1532 for In-System Configurable (ISC)
devices is intended to be programmed, reprogrammed, or
tested on the board via a physical and logical protocol.
Configuration through the Boundary-Scan port is always
available, independent of the mode selection. Selecting the
Boundary-Scan mode simply turns off the other modes.
Table 25: Virtex-II Configuration Mode Pin Settings
Configuration Mode⁽¹⁾
M2
M1
Master Serial
0
0
M0 CCLK Direction Data Width Serial D_OUT⁽²⁾
0
Out
1
Yes
Slave Serial
1
1
1
In
1
Yes
Master SelectMAP
0
1
1
Out
8
No
Slave SelectMAP
1
1
0
In
8
No
Boundary-Scan
1
0
1
N/A
1
No
Notes:
1. The HSWAP_EN pin controls the pull-ups. Setting M2, M1, and M0 selects the configuration mode, while the HSWAP_EN pin
controls whether or not the pull-ups are used.
2. Daisy chaining is possible only in modes where Serial D_OUT is used. For example, in SelectMAP modes, the first device does NOT
support daisy chaining of downstream devices.
Table 26 lists the total number of bits required to configure
each device.
Table 26: Virtex-II Bitstream Lengths
Device
# of Configuration Bits
XC2V40
338,976
XC2V80
598,816
XC2V250
1,593,632
XC2V500
2,560,544
XC2V1000
4,082,592
XC2V1500
5,170,208
XC2V2000
6,812,960
XC2V3000
10,494,368
XC2V4000
15,659,936
XC2V6000
21,849,504
XC2V8000
26,194,208
Configuration Sequence
The configuration of Virtex-II devices is a three-phase pro-
cess after Power On Reset or POR. POR occurs when
V_CCINT is greater than 1.2V, V_CCAUX is greater than 2.5V,
and V_CCO (bank 4) is greater than 1.5V. Once the POR volt-
ages have been reached, the three-phase process begins.
First, the configuration memory is cleared. Next, con-
figuration data is loaded into the memory, and finally, the
logic is activated by a start-up process.
Configuration is automatically initiated on power-up unless
it is delayed by the user. The INIT_B pin can be held Low
using an open-drain driver. An open-drain is required since
INIT_B is a bidirectional open-drain pin that is held Low by a
Virtex-II FPGA device while the configuration memory is
being cleared. Extending the time that the pin is Low causes
the configuration sequencer to wait. Thus, configuration is
delayed by preventing entry into the phase where data is
loaded.
The configuration process can also be initiated by asserting
the PROG_B pin. The end of the memory-clearing phase is
signaled by the INIT_B pin going High, and the completion
of the entire process is signaled by the DONE pin going
High. The Global Set/Reset (GSR) signal is pulsed after the
last frame of configuration data is written but before the
start-up sequence. The GSR signal resets all flip-flops on
the device.
The default start-up sequence is that one CCLK cycle after
DONE goes High, the global 3-state signal (GTS) is
released. This permits device outputs to turn on as neces-
sary. One CCLK cycle later, the Global Write Enable (GWE)
signal is released. This permits the internal storage ele-
DS031-2 (v3.5) November 5, 2007
Product Specification
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