Stratix Architecture
■
■
RapidIO
HyperTransport
Dedicated Circuitry
Stratix devices support source-synchronous interfacing with LVDS,
LVPECL, 3.3-V PCML, or HyperTransport signaling at up to 840 Mbps.
Stratix devices can transmit or receive serial channels along with a
low-speed or high-speed clock. The receiving device PLL multiplies the
clock by a integer factor W (W = 1 through 32). For example, a
HyperTransport application where the data rate is 800 Mbps and the
clock rate is 400 MHz would require that W be set to 2. The SERDES factor
J determines the parallel data width to deserialize from receivers or to
serialize for transmitters. The SERDES factor J can be set to 4, 7, 8, or 10
and does not have to equal the PLL clock-multiplication W value. For a J
factor of 1, the Stratix device bypasses the SERDES block. For a J factor of
2, the Stratix device bypasses the SERDES block, and the DDR input and
output registers are used in the IOE. See Figure 2–73.
Figure 2–73. High-Speed Differential I/O Receiver / Transmitter Interface Example
R4, R8, and R24
Interconnect
8
+
–
+
–
840 Mbps
840 Mbps
8
Data
8
Data
Dedicated
Receiver
Interface
Dedicated
Transmitter
Interface
Local
Interconnect
8×
rx_load_en
8×
105 MHz
Fast
PLL
tx_load_en
Regional or
global clock
An external pin or global or regional clock can drive the fast PLLs, which
can output up to three clocks: two multiplied high-speed differential I/O
clocks to drive the SERDES block and/or external pin, and a low-speed
clock to drive the logic array.
Altera Corporation
July 2005
2–137
Stratix Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
