ep2sgx30c Altera Corporation, ep2sgx30c Datasheet - Page 13

• Manufacturer Part Number: ep2sgx30c
• Description: Stratix Ii Gx Device Data Sheet
• Manufacturer: Altera Corporation

Figure 2–3. Clock Distribution for the Transmitters
Note to
(1)
Altera Corporation
October 2007
Reference Clocks
(refclks,
Global Clock (1) ,
Inter-Transceiver
Lines)
The global clock line must be driven by an input pin.
Figure
2–3:
Central Block
Transmitter Channel [3..2]
Transmitter Channel [1..0]
Transmitter PLL Block
The transmitter PLLs in each transceiver block clock the PMA and PCS
circuitry in the transmit path. The Quartus II software automatically
powers down the transmitter PLLs that are not used in the design.
Figure 2–4
The transmitter phase/frequency detector references the clock from one
of the following sources:
■
■
■
■
Two reference clocks, REFCLK0 and REFCLK1, are available per
transceiver block. The inter-transceiver block bus allows multiple
transceivers to use the same reference clocks. Each transceiver block has
one outgoing reference clock which connects to one inter-transceiver
block line. The incoming reference clock can be selected from five
inter-transceiver block lines IQ[4..0] or from the global clock line that
is driven by an input pin.
Reference clocks
Reference clock from the adjacent transceiver block
Inter-transceiver block clock lines
Global clock line driven by input pin
is a block diagram of the transmitter PLL.
Note (1)
Transmitter Local
Clock Divider Block
Transmitter Local
Clock Divider Block
Central Clock
Gen Block
Divider Block
Gen Block
TX Clock
TX Clock
Stratix II GX Device Handbook, Volume 1
Stratix II GX Architecture
Transmitter High-Speed &
Transmitter High-Speed &
Low-Speed Clocks
Low-Speed Clocks
2–5