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Figure 1-19: Clock Divider for a Transceiver Channel in Cyclone V Devices
To Serializer
/S
(4, 5, 8, 10)
PCIe Rateswitch
Circuit
/N
(1, 2, 4, 8)
x1 Clock Lines (1)
Fractional PLL
CMU PLL (2)
x6 Clock Lines (1)
xN Clock Lines (1)
To x6 Clock Lines (3)
PCIe Rateswitch
Control (4)
Serial Clock
Serial and Parallel
Clocks
(5)
Notes:
1. For information about the x1, x6, and xN clock lines, refer to Transceiver Clocking in Cyclone V Devices.
2. Only from the channel PLL in the same transceiver channel configured as a CMU PLL.
3. Applicable for central clock dividers only (clock dividers in channels 1 and 4).
4. The PCIe rateswitch circuit allows dynamic switching between Gen2 and Gen1 line rates in a PCIe Gen2 design.
5. The divider settings are configured automatically depending on the serialization factor. The selected divider setting is half
of the serialization factor.
Both types of clock dividers can divide the serial clock input to provide the parallel and serial clocks for the
serializer in the channel if you use clocks from the clock lines or transmit PLLs. The central clock divider
can additionally drive the x6 clock lines used to bond multiple channels.
In bonded channel configurations, both types of clock dividers can feed the serializer with the parallel and
serial clocks directly, without dividing them from the x6 or xN clock lines.
Related Information
Transceiver Clocking in Cyclone V Devices
Calibration Block
The calibration block calibrates the differential OCT resistance and analog circuitry in the transceiver PMA
to ensure the functionality is independent of PVT.
It is also used for duty cycle calibration of the clock line at serial data rates ≥ 4.9152 Gbps.
There is only one calibration block available for the Cyclone V transceiver PMA. It is located on the top left
of the device (same side as the transceiver channels).
Altera Corporation
Transceiver Architecture in Cyclone V Devices
1-25
Calibration Block
CV-53001
2013.05.06