Answers Database
4000E/EX: Can the BUFGLS, BUFGE, and BUFFCLK (4000X) and BUFGP and BUFGS (4000E) be driven with Internal Logic?
Record #1795
Product Family: Hardware
Product Line: 4000EX
Problem Title:
4000E/EX: Can the BUFGLS, BUFGE, and BUFFCLK (4000X) and BUFGP and
BUFGS (4000E) be driven with Internal Logic?
Problem Description:
Keywords:
BUFGS, BUFGP, BUFGLS, BUFGE, BUFFCLK
Urgency:
Standard
General Description:
For 4000X parts the BUFGLS (global low skew), BUFGE (global early) can all be
driven by either semi-dedicated pads or internal logic. While
the BUFFCLK (fast clock) can only be driven by the semi-dedicated IOB's,
and is not accessible from internal nets.
For 4000E parts the BUFGS (Secondary Global Buffers) can be driven by either sem
i-dedicated pads or internal logic. While BUFGP (Promary Global Buffers) must be
driven by the semi-dedicated pads.
Solution 1:
For a detailed description of each type of global clock buffer
in the XC4000X devices refer to pages 4-38 to 4-40 in the
1998 Xilinx programmable logic data book.
Solution 2:
For a detailed description of each type of global clock buffer
in the XC4000E devices refer to pages 4-36 to 4-37 in the
1998 Xilinx programmable logic data book.
End of Record #1795
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