GTS Transceiver PHY User Guide: Agilex™ 3 FPGAs and SoCs

ID 848344
Date 8/04/2025
Public
Document Table of Contents

3.3.10. Analog Parameter Options

You can use the transceiver analog parameter settings to tune the analog functions in the GTS PMAs while designing high-speed serial protocol solutions. You can use this feature to compensate for signal losses for high data rate communications.

You can choose to set the transceiver Analog TX and Analog RX parameters in the Analog Parameters tab of the GTS PMA/FEC Direct PHY IP GUI. You can also set the HSSI_PARAMETER in the .qsf file for a specific lane that you have configured within the GTS PMA/FEC Direct PHY IP GUI instance. Setting these parameters via the .qsf file has precedence over the analog parameter settings in the IP GUI. Refer to Configurable Quartus® Prime Software Settings for more information.

Figure 39. Analog Parameter Options in Parameter Editor
Table 32.  GTS PMA Transmitter Analog Settings
Parameter Values Description
Spread Spectrum DISABLE/ENABLE Specifies whether TX PLL reference clock is spread spectrum. Default value is DISABLE.
Note: Spread spectrum is not supported when you use the fast PLL mode of the TX PLL. The operating range of the VCO for the fast PLL mode is 13.5 GHz to 16.0 GHz. Data rates in this range and those represented by division factors of 2, 4, 8, and 16 are all excluded from enabling spread spectrum.
Enable TX P&N Invert DISABLE/ENABLE Invert TX serial outputs P and N pins. Default value is DISABLE .
Note: When you enable or disable the option, this setting applies the inversion to all the PMA lanes configured within the same GTS PMA/FEC Direct PHY IP instance. If you want to control this feature individually for each lane, you must use the QSF setting shown in the Configurable Quartus® Prime Software Settings section. In addition, if you use the Analog Parameter GUI options to invert the PMA P and N pin polarity, there is a requirement after you enter user mode that you must execute the Attribute access method steps explained in GTS Attribute Access Method Example 3 section. Follow the instruction in this example depending on the function required; either enabling or disabling the inversion of P and N pin of TX or RX PMAs.
TX EQ Post Tap 1, 1.0 step size 0 to 19 TX equalization control for Post Tap 1. Default value is 5 19.
TX EQ Main Tap, 1.0 step size 0 to 55 TX equalization control for Main Tap. Default value is 52 19.
TX EQ Pre Tap 1, 1.0 step size 0 to 15 TX equalization control for Pre Tap 1. Default value is 0.
TX EQ Pre Tap 2, 1.0 step size 0 to 7 TX equalization control for Pre Tap 2. Default value is 0.
Table 33.  GTS PMA Receiver Analog Settings
Parameter Values Description
RX Adaptation mode auto/manual/native Specifies the type of RX adaptation mode.

auto — Firmware based adaptation mode, also known as RX auto adaptation mode.

manual — Firmware based adaptation is disabled. In this adaptation mode, you must configure and control the RX equalizer parameters such as VGA Gain, High Frequency Boost and DFE Data Tap 1 to tune the RX links in Analog Parameters tab of the IP GUI or in .qsf assignment file.

You can change the RX Adaptation mode to manual if you are running at a data rate < 7 Gbps. However, if you are running at a low data rate but the link is lossy, you may need to use the auto adaptation mode.

native — the native adaptation mode must be enabled only for SDI and HDMI modes configured in IP GUI for data rates above 7 Gbps. You do not need to set the RX equalizer parameters if you select this adaptation mode.

Default value is auto.

Enable RX P&N Invert DISABLE/ENABLE Invert RX serial input P and N pins. Default value is DISABLE .
Note: When you enable or disable the option, this setting applies the inversion to all the PMA lanes configured within the same GTS PMA/FEC Direct PHY IP instance. If you want to control this feature individually for each lane, you must use the QSF setting shown in the Configurable Quartus® Prime Software Settings section. In addition, if you use the Analog Parameter GUI options to invert the PMA P and N pin polarity, there is a requirement after you enter user mode that you must execute the Attribute access method steps explained in GTS Attribute Access Method Example 3 section. Follow the instruction in this example depending on the function required; either enabling or disabling the inversion of P and N pin of TX or RX PMAs.

RX External Coupling Mode

AC/DC Specifies the type of external on-board coupling mode. Default value is AC.
Selects value of RX termination mode GROUNDED/DIFFERENTIAL Specifies the RX PMA buffer termination mode.

GROUNDED mode is used for AC coupled link.

DIFFERENTIAL mode is used for DC coupled link.

Default value is GROUNDED.
Selects value of RX onchip termination R_1(85 ohms)

R_2(100 ohms)

Selects RX on-chip termination resistor value. Default value is R_2(100 ohms).
RX EQ VGA Gain 0 to 63 Select the RX Equalization VGA Gain setting. This option is only available if you configure the RX Adaptation mode to manual. This setting is not available when RX adaptation mode is set to auto. Default value is 0 during auto adaptation mode, and 37 when configured in manual adaptation mode.
RX EQ High Frequency Boost 0 to 63 Select the RX Equalization High Frequency Boost setting. This option is only available if you configure the RX Adaptation mode to manual. This setting is not available when RX adaptation mode is set to auto. Default value is 0 during auto adaptation mode, and 29 when configured in manual adaptation mode.
RX EQ DFE Tap1 0 to 63 Select the RX Equalization DFE Tap1 setting. This option is only available if you configure the RX Adaptation mode to manual. This setting is not available when RX adaptation mode is set to auto. Default value is 0 during auto adaptation mode, and 23 when configured in manual adaptation mode.
19 This is the default value but you can change this value in the Analog Parameter GUI or the HSSI_PARAMETER in the .qsf file.