Visible to Intel only — GUID: nik1409872363714
Ixiasoft
Visible to Intel only — GUID: nik1409872363714
Ixiasoft
2.2.2.2. Bonded Channel Configurations
Clock Line | Transmitter PLL | Clock Path |
---|---|---|
x6, xN | ATX PLL26 | CMU PLL » central clock divider » x6 » xN » serializer |
CMU | CMU PLL » central clock divider » x6 » xN » serializer 25 | |
fPLL | fPLL » x1_fPLL » central clock divider » x6 » serializer 25 | |
x6 PLL Feedback Compensation 27 | ATX PLL 26 | ATX PLL » central clock divider » x6 » serializer |
CMU | CMU PLL » central clock divider » x6 » serializer |
- When using the fPLL to drive bonded channels, assign logical channel 0 to the channel where the central clock divider is used for fPLL clocks to access the x6 clock line. Using the preceding figure as an example, assign tx_serial_data[0] to the transmitter channel 4 pin location.
- For xN bonded configurations, the channel where the central clock divider resides (ch 1 or ch 4) can be used as a data channel as the parallel clock can be generated in this channel.
Bonded Channel Configurations Using the PLL Feedback Compensation Path for GZ Devices
You can bond channels across multiple banks by using the PLL feedback compensation path.
The PLL feedback compensation path loops the parallel clock, which is used by the PCS blocks, back to the transmitter PLL. The PLL feedback compensation path synchronizes the parallel clock used to clock the PCS blocks in all transceiver banks with the refclk. You can use the PLL feedback compensation path to reduce channel-to-channel skew, which is introduced by the clock divider in each transceiver bank.
To bond channels using the PLL feedback compensation path, the input reference clock frequency used by the transmitter PLL must be the same as the parallel clock that clocks the PCS of the same channel.
- Every transceiver bank with a bonded channel configured using the PLL feedback compensation path consumes a transmit PLL.
- fPLL does not support PLL feedback compensation when used as a TX PLL.
Transceiver Channel Placement Guidelines for fPLL in Transmit PLL Bonded Configuration (Except GZ Devices)
The fPLL as transmit PLL, when configured in bonded configuration, has placement restrictions. All channels need to be placed within one transceiver bank. A link cannot span across two banks. The channel placement must also be contiguous.