XC4VFX12-11FFG668C Xilinx Inc, XC4VFX12-11FFG668C Datasheet - Page 123

• Manufacturer Part Number: XC4VFX12-11FFG668C
• Description: IC FPGA VIRTEX-4 FX 12K 668FCBGA
• Manufacturer: Xilinx Inc
• Series: Virtex™-4r

Specifications of XC4VFX12-11FFG668C

• Number Of Logic Elements/cells: 12312
• Number Of Labs/clbs: 1368
• Total Ram Bits: 663552
• Number Of I /o: 320
• Voltage - Supply: 1.14 V ~ 1.26 V
• Mounting Type: Surface Mount
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 668-BBGA, FCBGA
• For Use With: HW-V4-ML403-UNI-G - EVALUATION PLATFORM VIRTEX-4HW-AFX-FF668-400 - BOARD DEV VIRTEX 4 FF668
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of Gates: -

Virtex-4 FPGA User Guide
UG070 (v2.6) December 1, 2008
Byte-Wide Write Enable
R
The byte-wide write enable feature of the block RAM gives the capability to write eight bit
(one byte) portions of incoming data. There are four independent byte-write enable inputs.
Each byte-write enable is associated with one byte of input data and one parity bit. All four
byte-write enable inputs must be driven in all data width configurations. This feature is
useful when using block RAM to interface with the PPC405. Byte-write enable is not
available in the Multi-rate FIFO. Byte-write enable is further described in the
RAMB16 Primitive Design Considerations”
enable logic.
When configured for a 36-bit or 18-bit wide data path, any port can restrict writing to
specified byte locations within the data word. If configured in READ_FIRST mode, the DO
bus shows the previous content of the whole addressed word. In WRITE_FIRST mode,
with identical Read and Write port widths, DO shows only the enabled newly written
byte(s). The other byte values must be ignored. In WRITE_FIRST mode with different
widths for Read and Write ports, all data on DO must be ignored.
WE[3:0]
A[13:0]
A14
DI
RAM_EXTENSION =
4
Figure 4-8: Byte-Wide Write Enable In Block RAM
NONE(0)
0
1
www.xilinx.com
Additional Block RAM Features in Virtex-4 Devices
“00”
D
D
D
D
D
section.
4
Figure 4-8
A[13:0]
A14
WE_Control
DI
WE[3:0]
shows the byte-wide write-
DO
UG070_4_08_033005
“Additional
DO
123