📶The Analog Devices Inc. AD9850 is a 32bit CMOS Direct Digital Synthesiser ( DDS ) device. Evaluation circuit boards with the device already mounted are widely available at low cost. However, in order to use the device ( perhaps only a quickly assembled frequency source is required ) a means still has to be provided of uploading to it 5 bytes of configuration settings, also a display to show the frequency and a rotary encoder for tuning. In the past at 'SpacerLabs' we have used a SPI-USB dongle and pc terminal software to acheive this.
📳A different and even more convenient method has recently been devised using an ESP32 micro-controller and our custom App for mobile devices📱called "DDSTerm". The App generates the 5 configuration bytes required from the user input frequency and phase data, then sends to the ESP32 using BluetoothⓇ. The ESP32 uploads the bytes using the SPI to the DDS board. The desired frequency [ ∿ ] is output. In the image example below frequency is 11.501MHz & bytes hexadecimal 178DD617C4.
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| App 'DDSTerm_v1.06' opened |
The image below shows the hardware setup used during development, comprising a typical ESP32 micro-controller in a 3-D printed case connected to the AD9850 DDS evaluation board mounted on a test-jig. The test-jig is not essential as the DDS board has pin-strip headers.
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| (Left) AD9850 board on test-jig, (R) ESP32 micro-controller inside enclosure |
𝌕The Android App "DDSTerm" and firmware for the ESP32 are available from us. Contact us by email or use the form below to receive more information. Note that AD9851 DDS boards are also supported.
SPI = Serial Peripheral Interface ( 3-wire bus )
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