• ADL5902
• AD7466

• CN0178

This lab presents the steps to setup an environment for using the EVAL-CN0178-SDPZ evaluation board together with the BeMicro SDK USB stick, the Nios II Embedded Development Suite (EDS) and the Micrium μC-Probe run-time monitoring tool. Below is presented a picture of the EVAL-CN0178-SDPZ Evaluation Board with the BeMicro SDK Platform.

Below is presented a picture of SDP-B Controller Board with the EVAL-CN0178-SDPZ Evaluation Board.

The CN0178 circuit uses the ADL5902 TruPwr? detector to measure the rms signal strength of RF signals with varying crest factors (peak-to-average ratio) over a dynamic range of approximately 65 dB and operates at frequencies from 50 MHz up to 9 GHz.

The measurement result is provided as serial data at the output of a 12-bit ADC (AD7466).

The ADL5902 is a true rms responding power detector that has a 65 dB measurement range when driven with a single-ended 50 Ω source. This feature makes the ADL5902 frequency versatile by eliminating the need for a balun or any other form of external input tuning for operation up to 9 GHz. The ADL5902 provides a solution in a variety of high frequency systems requiring an accurate measurement of signal power. Requiring only a single supply of 5 V and a few capacitors, it is easy to use and capable of being driven single-ended or with a balun for differential input drive. The ADL5902 can operate from 50 MHz to 9 GHz and can accept inputs from ?62 dBm to at least +3 dBm with large crest factors, such as GSM, CDMA, W-CDMA, TD-SCDMA, WiMAX, and LTE modulated signals.

The AD7466 is 12-bit, high speed, low power, successive approximation analog-to-digital converter (ADC). The part operates from a single 1.6 V to 3.6 V power supply and feature throughput rates up to 200 kSPS with low power dissipation. The part contains a low noise, wide bandwidth track-and-hold amplifier, which can handle input frequencies in excess of 3 MHz.

The EVAL-CN0178-SDP board contains the circuit to be evaluated, as described in this note. To power the EVAL-CN0178C-SDP evaluation board supply +6V between the +6 V and GND inputs.

• CN0178 Info - circuit note information
• ADL5902 Product Info - pricing, samples, datasheet
• AD7466 Product Info - pricing, samples, datasheet
• EVAL-CN0178-SDP evaluation board user guide
• BeMicro SDK
• Nios II Embedded Development Suite (EDS)
• Micrium uC-Probe

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.

Below is presented the list of required hardware items:

• Arrow Electronics BeMicro SDK FPGA-based MCU Evaluation Board
• BeMicro SDK/SDP Interposer adapter board
• EVAL-CN0178-SDPZ evaluation board
• Intel Pentium III or compatible Windows PC, running at 866MHz or faster, with a minimum of 512MB of system memory

Below is presented the list of required software tools:

• Quartus II Web Edition design software v11.0
• Nios II EDS v11.0
• uC-Probe run-time monitoring tool, version 2.5

The Quartus II design software and the Nios II EDS is available via the Altera Complete Design Suite DVD or by downloading from the web.

The Micrium uC/Probe Trial version 2.5 is available via download from the web at http://micrium.com/tools/ucprobe/trial/. After installation add to the “Path” system variable the entry “%QUARTUS_ROOTDIR%/bin/“ on the third position in the list.

• Lab Design Files

Create a folder called “ADIEvalBoardLab” on your PC and extract the cn0178_evalboardlab.zip archive to this folder. Make sure that there are NO SPACES in the directory path. After extracting the archive the following folders should be present in the ADIEvalBoardLab folder: FPGA, Software, ucProbeInterface, NiosCpu.

A notable challenge in embedded systems development is to overcome the lack of feedback that such systems typically provide. Many developers resort to blinking LEDs or instrumenting their code with printf() in order to determine whether or not their systems are running as expected. Micrium provides a unique tool named μC-Probe to assist these developers. With this tool, developers can effortlessly read and write the variables on a running embedded system. This section presents the steps required to install the Micrium uC-Probe software tool and to run the demonstration project for the ADI evaluation board. A description of the uC-Probe demonstration interface is provided.

Launch uC-Probe from the Start → All Programs → Micrium → uC-Probe.

Select uC-Probe options.

• Click on the uC-Probe icon on the top left portion of the screen.
• Click on the Options button to open the dialog box.

Set target board communication protocol as JTAG UART

• Click on the Communication tab icon on the top left portion of the dialog box
• Select the JTAG UART option.

Setup JTAG UART communication settings

• Select the JTAG-UART option from the Communication tab.
• Press the Open File button to select the JTAG Debug Information file (.jdi)
• Navigate to the ADIEvalBoardLab/FPGA folder and select the BeMicroSDK.jdi file. Press Open.
• Type the value 1 in the the Device Id window.

• Select uCProbe_uart(0) from the Instance Id pulldown menu.

• Press Apply and OK to exit the options menu. The embedded target has two UARTs. uC-Probe will be communicating with the uCProbe_uart.

• Click the Open option from the uC-Probe menu and select the file ADIEvalBoardLab/ucProbeInterface/CN0178_Interface.wsp.

• Before opening the interface uC-Probe will ask for a symbols file that must be associated with the interface. If the lab was done according to the steps provided in the Quick Evaluation section, select the file ADIEvalBoardLab/ucProbeInterface/ADIEvalBoard.elf to be loaded as a symbol file, otherwise select the file ADIEvalBoardLab/FPGA/software/ADIEvalBoard/ADIEvalBoard.elf to be loaded as a symbol file.

• Run the demonstration project by pressing the Play button.

The following figure presents the uC-Probe interface that can be used for monitoring and controlling the operation of the EVAL-CN0178-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 10 dBm, 0 dBm, ?10 dBm, and ?20 dBm were used.

The SLOPE and INTERCEPT calibration coefficients are calculated using the equations:

• SLOPE1 = ( CODE _1 – CODE_2) / (PIN_1 ? PIN_2)

• INTERCEPT1 = CODE_1 / (SLOPE_ADC × PIN_1)

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:

• PIN = (CODE / SLOPE) + INTERCEPT

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.