3–94
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Channel and Clock Multiplier Unit (CMU) PLL Reconfiguration
Input Reference Clock Requirements for Reusing MIFs
The MIF contains information about the input clock multiplexer and the
functional blocks that you selected during the ALT2GXB MegaWizard
instantiation. The Quartus II software generates a MIF for each channel.
This MIF can be used in any of the other channels in the device if you
satisfy the following two requirements for the input reference clocks:
■
The order of the clock inputs must be consistent. For instance,
assume that a MIF is generated for a transceiver channel in bank 13
and the clock source is connected to the
pll_inclk_rx_cruclk[0]
port. When the generated MIF is used
in a channel in other transceiver blocks (for example, bank 14), the
same clock source needs to be connected to the
pll_inclk_rx_cruclk[0]
port.
Figures 3–41
and
3–42
show the
incorrect and correct order of input reference clocks, respectively.
●
In
Figure 3–41
, the clocking is incorrect to reuse the MIF because
the input reference clock is not connected to the corresponding
pll_inclk_rx_cruclk[]
ports in the two instances.
Figure 3–41. Incorrect Input Reference Clock Connection to Reuse the MIF
156.25 MHz
clock source
Stratix II GX Device
bank 13
ALT2GXB
Instance 1
bank 14
ALT2GXB
Instance 2
156.25 MHz pll_inclk_rx_cruclk[0]
IQ Lines or Global Clock Network
pll_inclk_rx_cruclk[0]
pll_inclk_rx_cruclk[1]
pll_inclk_rx_cruclk[1]
125 MHz
clock source
125 MHz