This document presents the steps to setup an environment for using the EVAL-CN0150A-SDPZ evaluation board together with the Xilinx KC705 FPGA board, the Xilinx Embedded Development Kit (EDK) and the Micrium µC-Probe run-time monitoring tool. Below is presented a picture of the EVAL-CN0150A-SDPZ Evaluation Board with the Xilinx KC705 board.
For component evaluation and performance purposes, as opposed to quick prototyping, the user is directed to Analog Devices System Demonstration Platform (SDP). The SDP consists of a:
The EVAL-SDP-CB1Z controller board is part of Analog Devices SDP providing USB 2.0 high-speed connectivity to a PC computer running specific component evaluation software. Each SDP evaluation daughter board includes the necessary installation files needed for this performance testing. It's expected that the analog performance on the two platforms may differ.
Below is presented a picture of SDP-B Controller Board with the EVAL-CN0150A-SDPZ Evaluation Board.
The CN0150 circuit measures RF power at any frequency from 1 MHz to 8 GHz over a range of approximately 60 dB. The measurement result is provided as a digital code at the output of a 12-bit ADC with serial interface and integrated reference. The output of the RF detector has a glueless interface to the ADC and uses most of the ADC’s input range without further adjustment. A simple two-point system calibration is performed in the digital domain.
The AD8318 maintains accurate log conformance for signals of 1 MHz to 6 GHz and provides useful operation to 8 GHz. The device provides a typical output voltage temperature stability of ±0.5 dB.
The AD7887 ADC can be configured for either dual or single channel operation via the on-chip control register. There is a default single-channel mode that allows the AD7887 to be operated as a read-only ADC, thereby simplifying the control logic.
The EVAL-CN0150A-SDPZ board contains the circuit to be evaluated, as described in this note. To power the EVAL-CN0150A-SDPZ evaluation board supply +6V between the +6 V and GND inputs.
The first objective is to ensure that you have all of the items needed and to install the software tools so that you are ready to create and run the evaluation project.
The following table presents a short description the reference design archive contents.
|Bit||Contains the KC705 configuration file that can be used to program the system for quick evaluation.|
|Microblaze||Contains the EDK 13.4 project for the Microblaze softcore that will be implemented in the KC705 FPGA.|
|Software||Contains the source files of the software project that will be run by the Microblaze processor.|
|uCProbeInterface||Contains the uCProbe interface and the .elf symbols file used by uC-Probe to access data from the Microbalze memory.|
Before connecting the ADI evaluation board to the Xilinx KC705 make sure that the VADJ_FPGA voltage of the KC705 is set to 3.3V. For more details on how to change the setting for VADJ_FPGA visit the Xilinx KC705 product page.
At this point everything is set up and it is possible to start the evaluation of the ADI hardware through the controls in the uC-Probe application provided in the reference design.
Launch uC-Probe from the Start → All Programs → Micrium → uC-Probe.
Select uC-Probe options.
Set target board communication protocol as RS-232
Setup RS-232 communication settings
The following figure presents the uC-Probe interface that can be used for monitoring and controlling the operation of the EVAL-CN0150A-SDPZ evaluation board.
Section A is used to activate the board and monitor activity. The communication with the board is activated / deactivated by toggling the ON/OFF switch. The Activity LED turns green when the communication is active. If the ON/OFF switch is set to ON and the Activity LED is BLACK it means that there is a communication problem with the board.
Section B is used to select the sample size and to initiate a data acquisition. The value of the “Sample Size” slider controls the number of datapoints to collect. From these datapoints is calculated an average value, which is stored in ADC Code Column (the position is auto incremented). Acquire Data button initiates a data acquisition.
Section C is used to store the calibration data and to display the calculated information. The calibration is performed by applying four known signal levels to the ADL5902 and measuring the corresponding output codes from the ADC. The calibration points chosen should be within the linear operating range of the device. In this example, calibration points at -30 dBm, -20 dBm, -10 dBm, and 0 dBm were used.
User has to add manually ADC Code and Input Power for each signal, in the Calibration Data section. Frequency and temperature are optional. Slope and Intercept are calculated by the interface.
The SLOPE and INTERCEPT calibration coefficients are calculated using the equations:
This calculation is then repeated using CODE_2/CODE_3 and CODE_3/CODE_4 to calculate SLOPE2/INTERCEPT2 and SLOPE3/INTERCEPT3, respectively.
When the circuit is in operation in the field, these calibration coefficients are used to calculate an unknown input power level, PIN, using the equation:
In order to retrieve the appropriate SLOPE and INTERCEPT calibration coefficients during circuit operation, the observed CODE from the ADC must be compared to CODE_1, CODE_2, CODE_3, and CODE_4. For example if the CODE from the ADC is between CODE_1 and CODE_2, then the SLOPE1 and INTERCEPT1 should be used.
The interface chooses the slope and intercept for each ADC code and calculates the Power. For the error to be calculated, it is necessary to add manually the Input Power. Frequency and temperature are optional.
In case there is a communication problem with the board the follwing actions can be perfomed in order to try to fix the issues: