Chapter 5: Clock Networks and PLLs in Arria II Devices
5–23
PLLs in Arria II Devices
December 2010
Altera Corporation
Arria II Device Handbook Volume 1: Device Interfaces and Integration
shows the clock I/O pins associated with the top and bottom PLLs.
For Arria II GZ devices, any of the output counters (
C[9..0]
on the top and bottom
PLLs and
C[6..0]
on the left and right PLLs) or the
M
counter can feed the dedicated
external clock outputs, as shown in
and
. Therefore, one
counter or frequency can drive all output pins available from a given PLL. Each left
and right PLL supports two clock I/O pins, configured as either two single-ended
I/Os or one differential I/O pair. When using both pins as single-ended I/Os, one of
them can be the clock output while the other pin is the external feedback input (FB)
pin. Therefore, for single-ended I/O standards, the left and right PLLs only support
external feedback mode.
Figure 5–18. External Clock Outputs for Top and Bottom PLLs in Arria II GZ Devices
(1) You can feed these clock output pins using any one of the
C[9..0]
, or
m
counters
.
(2) The
CLKOUT0p
and
CLKOUT0n
pins can be either single-ended or differential clock outputs. The
CLKOUT1
and
CLKOUT2
pins are
dual-purpose I/O pins that you can use as two single-ended outputs or one differential external feedback input pin. The
CLKOUT3
and
CLKOUT4
pins are two single-ended output pins.
(3) These external clock enable signals are available only when you use the ALTCLKCTRL megafunction.
Top/Bottom
PLLs
C2
C3
C4
C6
C7
C5
PLL_<#>_CLKOUT3
(1), (2)
C8
C0
C1
C9
Internal Logic
PLL_<#>_CLKOUT4
(1), (2)
PLL_<#>_FBn/CLKOUT2
(1), (2)
PLL_<#>_FBp/CLKOUT1
(1), (2)
PLL_<#>_CLKOUT0n
(1), (2)
PLL_<#>_CLKOUT0p
(1), (2)
clkena0
(3)
clkena1
(3)
clkena3
(3)
clkena2
(3)
clkena4
(3)
clkena5
(3)
m(fbout)