HC4GX15 Datasheet, PDF (130/668 Pages) Altera Corporation – HardCopy IV Device Handbook

8–20
Chapter 8: High-Speed Differential I/O Interfaces and DPA in HardCopy IV Devices
Guidelines for DPA-Disabled Differential Channels
Figure 8–20. Invalid Placement of DPA-Enabled Differential I/Os Driven by Both Center Left/Right
PLLs
DPA-enabled
Diff I/O
DPA-enabled
Diff I/O
DPA-enabled
Diff I/O
DPA-enabled
Diff I/O
Reference
CLK
Center
Left/Right PLL
Center
Left/Right PLL
Reference
CLK
DPA-enabled
Diff I/O
DPA-enabled
Diff I/O
DPA-enabled
Diff I/O
DPA-enabled
Diff I/O
Guidelines for DPA-Disabled Differential Channels
When DPA-disabled channels are used in the left and right banks of a HardCopy IV
device, you must adhere to the guidelines in the following sections.
DPA-Disabled Channel Driving Distance
Each left or right PLL can drive all the DPA-disabled channels in the entire bank.
Using Corner and Center Left and Right PLLs
The following show how you can use corner and center left and right PLLs:
■ You can use a corner left or right PLL (PLL_L1, PLL_L4, PLL_R1, and PLL_R4) to
drive all transmitter channels and a center left or right PLL (PLL_L2, PLL_L3,
PLL_R2, and PLL_R3) to drive all DPA-disabled receiver channels within the
same differential bank. A transmitter channel and a receiver channel in the same
LAB row can be driven by two different PLLs, as shown in Figure 8–21.
■ A corner left or right PLL and a center left or right PLL can drive duplex channels
in the same differential bank as long as the channels driven by each PLL are not
interleaved. No separation is necessary between the group of channels driven by
the corner and center left or right PLLs. Refer to Figure 8–21 and Figure 8–22.
HardCopy IV Device Handbook, Volume 1
© January 2010 Altera Corporation