3–42
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Channel and PMA Controls Reconfiguration
alternate protocol. This means that GIGE is achieved with the main PLL
and the alternate PLL/input reference clock configuration is
SONET/SDH OC48. Assume that you set the
Logical Reference Index
option value to
0
(in the
Reconfig
tab).
By setting the logical reference index to
0
, you provide the Quartus II
software with the following information.
Selection values for the two MUXs mentioned above. The signal name
MuxSelect*
is an assumed name.
■
Logical reference index = alternate input reference clock input leg
■
MuxSelect* = ~(logical reference index)
In this case, since the logical reference index is set to
0
(represents the
SONET/SDH), the TX PLL based on GIGE is routed to input1 of the clock
MUX, and the alternate PLL configured for SONET/SDH is connected to
input0 of the clock MUX. In the GIGE MIF, the clock MUX select value is
set to
1
to choose the clock from the GIGE TX PLL.
Figures 3–20
and
3–21
show the clock MUX connections for GIGE and
SONET/SDH, respectively.
Figure 3–20. TX PLL for GIGE and SONET/SDH OC48 Mode Reconfiguration
CMU Block
TX Channel
Clocking
Block
TX Channel
RX Channel
0
1
TX High Speed Clocks
TX PLL 1
(SONET)
TX PLL 2
(GIGE)
pll_inclk_alt
(77.76MHz)
pll_inclk
(125 MHz)
625MHz
1244.16 MHz
rx_cruclk
(125 MHz)
rx_cruclk_alt
(77.76 MHz)
MuxSelect =1
MuxSelect =1
0
1
Clock to CDR
local refclk