The Oscilloscope Simulation System base on Silabs MCU device EFM8UB1 is intended to bring a tool to sample ADC value and display it as waveform on a computer screen, Through a combination of hardware and software, it looks like a real oscilloscope.
The software architecture of system consist of firmware running on EFM8UB1 STK and application running on a computer. The GUI application running on a computer is developed by python 2.7, pyside2, Qt5, and USBxpress library.
The hardware consists of a computer host and a EFM8UB1EK device, the EFM8UB1EK is connected with the computer with USB cable. Use EFM8UB1 to sample the adc voltage value, send the collected data to the host via USB. The block is illustrated below.
There are most of library made by Silabs is developed with Python 2.7 32-bit. Please download and install Python 2.7 32-bit, the download link is below. https://www.python.org/downloads/release/python-2715/
Official release wheels of Qt For Python can be installed regularly via pip:
pip install pyside2Pre-release (snapshot) wheels containing the latest code changes are available at http://download.qt.io/snapshots/ci/pyside/
For example you can install the latest 5.11 snapshot wheel using:
pip install --index-url=http://download.qt.io/snapshots/ci/pyside/5.11/latest/ pyside2 --trusted-host download.qt.ioSee more info from http://wiki.qt.io/Qt_for_Python/GettingStarted.
The compiled firmware is located directory Bin/, program the Hex file to Silabs device EFM8 Universal Bee Starter Kit (SLSTK2000A) to make it as a oscilloscope device. See more info about from Silabs device EFM8 Universal Bee Starter Kit https://www.silabs.com/products/development-tools/mcu/8-bit/slstk2000a-efm8-universal-bee-starter-kit
Connect the EFM8UB1EK device and a computer with USB cable.
Download the software/ to local and run the application with command below.
python.exe main.pyApplication starts with a login widget as shown below. The component 1 is device combobox which shows the connected EFM8UB1EK device, the component 2 is a pushbutton.
The device shown in combobox will be open and application jump to a main widget when the pushbutton is pressed.
District 1 is a canvas which used to display the waveform, when cursor is in this district the time and ADC value of cursor position will be shown.
District 2 is display district.They are zoom in pushbutton, zoom out pushbutton, enable ADC pushbutton and single trigger button from left to right in this district.
District 3 is used to control 3 LED on EFM8UB1EK device.
District 4 is used to enable channel, there are two channel available which routed to GPIO pin1.7 and GPIO pin1.2 respectively.
District 5 is frequency district, the sample frequency will be set to the value shown in combobox when the set pushbutton is pushed.
The current information will be shown in the district 6.
Suppose have all the required environments and equipment, you can start sampling by following the steps below.
- Connect the device and host
- Execute GUI application
- Choose the required device in combobox and press enter button
- Check the required channel
- Choose the appropriate frequency and then press set button
- Push the enable ADC button in district 2
After that, the waveform will be display in district 1.
In order to facilitate the later function expansion, a flexible protocol was developed.Every operation will be a item of command which consists of preamble byte, command byte, value length and value. The preamble byte is a fixed value 0xAA, the command byte shows the specific operation, the third byte followed by value is length of value. The table shown below lists the command has been taken. If one want to develop a new command, he can just start with 0x60.
The oscilloscope simulation system is used to sample analog voltage and show it as waveform. It provides two channel to sample the voltage signal, supports zoom out and zoom and is able to display voltage and time information on mouse cursor point. which make it looks like a real oscilloscope. It is significant tool to measure analog voltage for engineer.