Hybrid Memory Cube Controller IP Core User Guide - Intel Stratix 10 Beta Version

ID 683854
Date 8/08/2016
Public
Document Table of Contents

2.5.2.1. Adding the External PLL

The HMC Controller IP core requires that you generate and connect an external PLL IP core. You must generate the PLL IP core required to clock the TX transceiver channels that are configured as HMC Controller IP core lanes. The ATX PLL IP core configures the transceiver PLL in the transceiver in hardware, but you must generate the transceiver PLL IP core separately from the HMC Controller IP core in software. Alternatively, you can configure an fPLL in transceiver mode. If you do not generate and connect the PLL IP core, the HMC Controller IP core does not function correctly in hardware.

You can use the IP Catalog to generate the external PLL IP core that configures a transceiver PLL on the device.

In the transceiver PLL parameter editor, you must configure the PLL IP core in the xN bonding configuration. In addition, you must set the following parameter values:

  • PLL output frequency to one half of the per-lane data rate of the IP core variation. The transceiver performs dual edge clocking, using both the rising and falling edges of the input clock from the PLL. Therefore, this PLL output frequency setting drives the transceiver with the correct clock for the lanes that connect to the HMC device.
  • PMA interface width to 32.
  • PLL integer reference clock frequency (ATX PLL) or Desired reference clock frequency (fPLL).

    Intel recommends that you specify 125 MHz, 156.25 MHz, or 166.67 MHz. You can theoretically specify any reference clock frequency from which the PLL can generate the required output clock frequency. However, you must drive this TX PLL and the RX CDR PLL (rx_cdr_refclk0 input signal to the HMC Controller IP core) and the HMC device reference clock input signals (REFCLKP and REFCLKN) from the same clock source.

    Note: You must drive the external PLL reference clock input signal at the frequency you specify for this parameter.

In xN bonding mode, a single PLL is sufficient to drive the channels in the configured transceiver blocks. Recall that your HMC link TX serial lanes must be configured in order in adjacent physical transceiver channels so that these lanes configure a maximum of three transceiver blocks. You can view I/O constraints that enforce these requirements in the design example Quartus Settings File hmcc_example.qsf provided with the HMC Controller IP core.

Note: The HMC Controller IP core does not support PLL feedback compensation bonding.

The PLL output connects directly to the x6 network for its transceiver block and drives additional transceiver blocks through the xN clock network.

Figure 9. Transceiver PLL Connections Example with xN Bonding SchemeExample connections between an HMC Controller IP core and a single ATX PLL IP core in xN bonding mode.

You must connect the external PLL signals and the HMC Controller IP core transceiver TX PLL interface signals according to the following rules:

HMC Controller Signal Connects to TX PLL Signal
tx_bonding_clocks[5:0] input signal for HMC lane N tx_bonding_clocks[5:0] output vector of PLL IP core for the transceiver block in which lane N is configured.

In the case of xN bonding, a single PLL connects to the xN clock network and the tx_bonding_clocks[5:0] input pins for HMC lanes in a different transceiver block from the configured PLL receive the clock from the xN clock network.

pll_locked input signal pll_locked output signal of the external PLL for all of the HMC lanes.
pll_cal_busy input signal pll_cal_busy output signal of the external PLL for all of the HMC lanes.

User logic must provide the connections.