The code is written so that no external trigger signal is required. Any changes in the code (addition of time delays, lines), clock frequency, crystal value, changes in settings of oscilloscope may lead to a distorted image. The code is optimised and properly synchronised with time for proper display of images on the oscilloscope. 2 and the stored image will be displayed. Connect the oscilloscope probe to the circuit as shown in Fig. 5: Copying byte code of the image in the programĬompile the code and burn it in the microcontroller using a suitable programmer. 4: Loading the BMP image to get the byte codeĬopy the 504 bytes of byte code of the image and paste it in the source code as shown in Fig. Get the byte code of the BMP image by directly loading the image in the Nokia 3310 tab as shown in Fig. Open GLCD bitmap editor from the tool menu as shown in Fig. Convert the image to monochrome BMP format by saving the resized image as monochrome BMP format in MS-Paint.ĭownload microC PRO for AVR from. Now resize the image to 84x32 (widthxheight) size. Trigger slope set to negative (may be neglected) The below-mentioned settings must be made in the oscilloscope for proper display of images (any deviation in values will lead to distorted images):ģ. By individual switching of the pixels across a column till the trace moves to the next column, an image can be displayed. The 32 pixels across a single column constitute 4 bytes. This is how the pixel array is generated on the screen. As the trace moves horizontally, it forms an array of pixels across the screen having 32 rows. By switching the values from 0 to 31 very fast, we form a pixel of 32 dots across a single column. Each of the 32 pixels across a single column in the screen is assigned a particular voltage level (digital values from 0 to 31) as seen in the code. The analogue values are applied to the y-input of the scope. ![]() The trace is set at this value for proper persistence of vision and in synchronisation with the timing of the code for proper display. The trace of the oscilloscope runs with internal trigger set at 10ms (time/ div). More than one image can be stored in new arrays until the Flash memory saturates. So, for persistence of vision, the trace is repeated continuously for a certain number of cycles (50 here in the code). The loop is repeated continuously as there is no DDRAM (data display RAM) to store the pixel information. The details are given in comment lines of the code. The vertical trace movement is synchronised by the 20ps delay from one column to the next. On state is represented by a value of 1 to 31 and an off state by 0. The myte array stores the pixel data of 32 pixels along a column, indicating the on/off states. The byte codes of the image is in the intel array which is stored in Flash memory. The code is written such that it accepts byte codes in pages and columns format. The hex code is burnt in the microcontroller using a suitable programmer. The software is written in C language and compiled using Programmer's Notepad of WinAVR software. An R-2R ladder network DAC (digital-to-analogue converter) is used to convert digital (8-bit) values from the microcontroller to analogue values that are input to the oscilloscope. A 16MHz crystal is connected across its pins 12 and 13 to provide basic clock. ![]() It has 16kB insystem programmable Flash memory, 512 bytes of EEPROM and 1kB SRAM. ![]() The heart of the project is ATmega16 microcontroller - a low-power CMOS 8-bit chip based on AVR enhanced RISC architecture. 2: Circuit for oscilloscope as image viewer 1: Image display on an analogue oscilloscopeįig. 1 shows 'EFY' image on the oscilloscope.įig. Here we present a project where you can display any image or multiple images (monochrome) on an analogue oscilloscope. But displaying a monochrome bitmap image on an oscilloscope is a challenging yet interesting task. There is a luminous spot which moves over the display area in response to the input voltage. It is nothing but a fast x-y plotter that displays an input signal versus another signal or time. Cathode ray oscilloscope (CRO) is a versatile laboratory instrument which is used to display, measure and analyse electrical signals.
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