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Using PPS ADRV9009-ZU11EG on ADRV2CRR-FMC

Hi,

We plan to use GPS PPS on ADRV9009-ZU11EG.

Do I need to use a reference clock generator that comes with a PPS output? Any particular board do you suggest?

If possible please let me know how we can practice a test?

Would you please let me know if there is any documentation available for using the PPS?

Thanks

  • If you are just trying to discipline the ref clock, a common approach would be to go 1 PPS -> AD9548 -> HMC7044. If you have a high enough speed clock out from your GPS receiver you could feed it into the HMC7044 directly.

    I would recommend asking in the Clocking Forum as well about GPS disciplining for HMC7044.

    -Travis

  • Thanks Travis,

    I will post the question in the Clocking Forum as well. 

    From the ADRV9009-ZU11EG side, do I need to do any configuration?

    If there is any documentation please let me know. 

  • Hi, did you succeed on configuring the ADRV9009-ZU11EG on ADRV2CRR-FMC to work properly by applying a PPS signal on the PPS input of the ADRV2CRR-FMC ?

    Thanks, Joel

  • No, for now, but later we will back to this.

    Please share if you had any updates.

    Thanks

  • Hello, got back some answers about PPS on ADRV2CRR.

    There are two main problems:

    - AD9545 has not been added to the device tree... (it will be added soon). This can be easily fixed following the discussion I had on this forum.

    - PPS do not works properly on the current ADRV2CRR HW ... "AD9545, without the OCXO for system clock compensation, will eventually lock on the 1PPS but will spontaneously loose PLL lock from time to time, this of course degrading the performance". This issue will be fixed by substituting the XO with a more stable OCXO. Unfortunately this issue can't be solved on the current HW.

    Joel

  • Hi, just in case you want to try PPS or 10 MHz synchronization on J4 (system-user.dtsi):

    /include/ "system-conf.dtsi"
    #include <dt-bindings/clock/ad9545.h>
    //#define REF_A_10MHZ 
    / {
    	ref_clk0: ref_clk_0 {
    		compatible = "fixed-clock";
    		#clock-cells = <1>;
    #ifdef REF_A_10MHZ
    		clock-frequency  = <10000000>; // 10MHz Ref. A
    #else
    		clock-frequency  = <1>;          // 1PPS Ref A.
    #endif		
    		
    		clock-output-names = "Ref-A";
    	};
    };
    
    /*
     * I2C1
     */
    
    &i2c1 {
    	status = "okay";
    	clock-frequency = <400000>;
    	pinctrl-names = "gpio";
    	pinctrl-0 = <&pinctrl_i2c1_gpio>;
    	scl-gpios = <&gpio 32 GPIO_ACTIVE_HIGH>;
    	sda-gpios = <&gpio 33 GPIO_ACTIVE_HIGH>;
    
    	i2c-mux@70 { /* u19 */
    		compatible = "nxp,pca9548"; /* TCA9548 */
    		#address-cells = <1>;
    		#size-cells = <0>;
    		reg = <0x70>;
    
    		i2c@0 { /* Audio ADAU1761 */
    			#address-cells = <1>;
    			#size-cells = <0>;
    			reg = <0>;
    
    			adau1761: adau1761@3b {
    				compatible = "adi,adau1761";
    				reg = <0x3b>;
    
    				clocks = <&audio_clock>;
    				clock-names = "mclk";
    
    				#sound-dai-cells = <0>;
    			};
    
    		};
    		i2c@1 { /* AD9545 */
    			#address-cells = <1>;
    			#size-cells = <0>;
    			reg = <1>;
    
    			ad9545_clock: ad9545@4a {
    				compatible = "adi,ad9545";
    				reg = <0x4a>;
    
    				#address-cells = <1>;
    				#size-cells = <0>;
    
    				adi,ref-crystal;
    				adi,ref-frequency-hz = <49152000>;
    
    				clock-names = "Ref-A";
    				clocks = <&ref_clk0 0>;
    
    				#clock-cells = <2>;
    
    				assigned-clocks = <&ad9545_clock AD9545_CLK_NCO AD9545_NCO0>,
    						  <&ad9545_clock AD9545_CLK_PLL AD9545_PLL0>,
    						  <&ad9545_clock AD9545_CLK_OUT AD9545_Q0A>;
    				assigned-clock-rates = <10000>, <1413120000>, <30720000>;
    				assigned-clock-phases = <0>, <0>, <0>, <180>;
    
    				aux-nco-clk@AD9545_NCO0 {
    					reg = <AD9545_NCO0>;
    					adi,freq-lock-threshold-ps = <16000000>;
    					adi,phase-lock-threshold-ps = <16000000>;
    				};
    
    				/* Ref A (J4) 10Mhz input */
    				ref-input-clk@0 {
    					reg = <0>;
    					adi,single-ended-mode = <DRIVER_MODE_DC_COUPLED_1V8>;
    					adi,ref-dtol-pbb = <10000000>;
    					adi,ref-monitor-hysteresis-pbb = <87500>;
    					adi,freq-lock-threshold-ps = <0xFFFFFF>;
    					adi,phase-lock-threshold-ps = <0xFFFFFF>;
    
    					
    #ifdef REF_A_10MHZ			/* 10 MHz Ref. A*/	
    					adi,r-divider-ratio = <200>; // 10MHz Ref. A					
    					adi,freq-lock-fill-rate = <20>;
    					adi,phase-lock-fill-rate = <20>;
    					adi,ref-validation-timer-ms = <1>;					
    #else					/* 1PPS Ref. A*/
    					adi,r-divider-ratio = <1>;    // 1PPS Ref. A 
    					adi,freq-lock-fill-rate = <200>;
    					adi,phase-lock-fill-rate = <200>;
    					adi,ref-validation-timer-ms = <10000>;
    #endif
    					adi,freq-lock-drain-rate = <20>;
    					adi,phase-lock-drain-rate = <20>;
    				};
    
    				ad9545_apll0: pll-clk@AD9545_PLL0 {
    					reg = <AD9545_PLL0>;
    
    					#address-cells = <1>;
    					#size-cells = <0>;
    
    					profile@0 {
    						reg = <0>;
    						adi,pll-source = <4>;
    						adi,profile-priority = <20>;
    						adi,pll-loop-bandwidth-uhz = <200000000>;
    					};
    
    #ifdef REF_A_10MHZ			/* 10 MHz Ref. A*/		
    					profile@1 {
    						reg = <1>;
    						adi,pll-source = <0>;
    						adi,profile-priority = <0>;					
    						adi,pll-loop-bandwidth-uhz = <200000000>;
    
    					};
    #else					/* 1PPS Ref. A*/
    					profile@1 {
    						reg = <1>;
    						adi,pll-source = <0>;
    						adi,profile-priority = <0>;
    						adi,pll-loop-bandwidth-uhz = <50000>;
    						adi,fast-acq-excess-bw = <8>;
    						adi,fast-acq-timeout-ms = <10000>;
    						adi,fast-acq-lock-settle-ms = <100>;
    					};
    #endif					
    				};
    
    				output-clk@AD9545_Q0A {
    					reg = <AD9545_Q0A>;
    					adi,output-mode = <DRIVER_MODE_SINGLE_DIV_DIF>;
    					adi,current-source-microamp = <15000>;
    				};
    			};
    
    		};
    		i2c@2 { /* PTN5150 */
    			#address-cells = <1>;
    			#size-cells = <0>;
    			reg = <2>;
    
    			/* 1D */
    
    		};
    		i2c@3 { /* QSFP */
    			#address-cells = <1>;
    			#size-cells = <0>;
    			reg = <3>;
    
    			eeprom@50 {
    				compatible = "at24,24c02";
    				reg = <0x50>;
    			};
    		};
    		i2c@4 { /* SFP+ */
    			#address-cells = <1>;
    			#size-cells = <0>;
    			reg = <4>;
    
    			eeprom@50 {
    				compatible = "at24,24c02";
    				reg = <0x50>;
    			};
    
    		};
    		i2c@5 { /* FMC HPC */
    			#address-cells = <1>;
    			#size-cells = <0>;
    			reg = <5>;
    
    // 			ad7291@2f {
    // 				compatible = "adi,ad7291";
    // 				reg = <0x2f>;
    // 			};
    
    			eeprom@50 {
    				compatible = "at24,24c02";
    				reg = <0x50>;
    			};
    		};
    	};
    };

    I tried it on my ADRV2CRR using a PPS from a UBLOX F9P unit and it seems that the AD9545 works properly ... I didn't observed loss of lock so far (but I guess I've to increase drastically the observation time to being able to see a loss of lock).

    Uncomment the //#define REF_A_10MHZ macro for using the 10 MHz reference instead.

    Joel

  • Can someone vouch for the configuration of the system-user.dtsi provided provided by @Joebre in order to get 10MHz external reference to work on the adrv9009 zu11eg.