DdsModTerm software for AD9850/51 modules

🔘In the post 📮dated 📅27 July 2023, about how a µ-controller and a smart phone🖁 App could be used to upload 🠝 configuration settings to  modules based on AD9850 and AD9851 DDS chips in order to generate a frequency, it was briefly mentioned that  a USB dongle and pc interface software was another method in use here. As that software has recently been updated it would now be a good time to give a description of that method also.

The SpacerLabs dedicated pc 💻software called "DdsModTerm" is the user interface and was first released in about 2015. Since then there have been 15 revisions; the latest appearing this month.

'DdsModTerm' user interface

The clock 🕰frequency and the required output frequency and phase are entered, either manually or by recall from memory. By clicking 'Confirm', the software generates the 5 configuration bytes required from the user input data. In the example in the image above the output frequency is 137700Hz & bytes hexadecimal 00C88AC604. The pc 💻is connected to the serial data interface of the DDS module board via a COM port and the SpacerLabs USB-SPI dongle. Clicking 'Update DDS' then uploads the bytes using  SPI protocol to the registers of the DDS chip and the programmed frequency  ∿  is then present on the output. 

(L) USB-SPI dongle (R) AD9851 DDS chip evaluation board on adaptor

Other features of the software include up/down step 🪜tuning, slider tuning control, eeprom view, 3 memories for storing frequency, saving custom clock🕓, alias frequencies calculated, and general purpose output ( GPO ) toggling on/off.

The dongle and software are available from us. Post a comment, contact us by email or use the form below to receive more information. Note that both AD9850 & AD9851 DDS devices are supported.🔘

( Click on images to enlarge detail. )

SPI = Serial Peripheral Interface, 3-wire bus.

AD9850, AD9851 : 🔗Analog Devices Inc. parts, 32-bit CMOS Direct Digital Synthesiser (DDS) chips.

AD9850 DDS Module with mobile App configurator

📶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.

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.

(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 )