5–18
Chapter 5: Clock Networks and PLLs in Arria II Devices
Clock Networks in Arria II Devices
Arria II Device Handbook Volume 1: Device Interfaces and Integration
December 2010
Altera Corporation
f
For more information about the clock control block and its supported features in the
Quartus II software, refer to the
Clock Control Block (ALTCLKCTRL) Megafunction User
Figure 5–14. Clock Input Multiplexer Logic for Arria II GX PLLs
Notes to
(1) Input clock multiplexing is controlled through a configuration file (
.sof
or
.pof
) only; it cannot be dynamically controlled when the device is
operating in user mode.
(2) Dedicated clock input pins to the PLLs: n=4 for
PLL_4
; n=4 or 8 for
PLL_3
; n=8 or 12 for
PLL_2
; and n=12 for
PLL_1
.
(3) You can drive the GCLK or RCLK clock input with an output from another PLL, a pin-driven GCLK or RCLK, or through a clock control block,
provided the clock control block is fed by an output from another PLL or a pin-driven dedicated GCLK or RCLK. An internally generated global
signal or general purpose I/O pin cannot drive the PLL.
4
4
(1)
(1)
inclk0
inclk1
To the clock
switchover block
CLK[n+3..n]
(2)
GCLK / RCLK input
(3)
Adjacent PLL output
Figure 5–15. Clock Input Multiplexer Logic for Arria II GZ devices
(1) When the device is operating in user mode, input clock multiplexing is controlled through a configuration file
(
.sof
or
.pof
) only and cannot be dynamically controlled.
(2) n=0 for L2 and L3 PLLs; n=4 for B1 and B2 PLLs; n=8 for R2 and R3 PLLs, and n=12 for T1 and T2 PLLs.
(3) You can drive the GCLK or RCLK input using an output from another PLL, a pin-driven GCLK or RCLK, or through a clock control block provided
the clock control block is fed by an output from another PLL or a pin-driven dedicated GCLK or RCLK. An internally generated global signal or
general purpose I/O pin cannot drive the PLL.
4
4
(1)
(1)
inclk0
inclk1
To the clock
switchover block
clk[n+3..n]
(2)
GCLK / RCLK input
(3)
Adjacent PLL output