[Facts] Raspberry Pi + I²C + MCP23017: digital output toggle timespan (Bash, Python, C)

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purpose: measuring the timespan between rising/falling-edge (=off/on/off-change) of a digital-output-bank (GPA0…GPA7) testing equipment: -Raspberry Pi 3 Modell B-I2C-adress of MCP23017-chip = 0x20-MCP23017 register-adress of 8 digital-outputs: 0x14-Owon SDS7102 digital ocsilloscope conclusion: I²C-baudrate bash Python C 100.000 5,18 ms @ 75 … Continued

[Howto] GTK+ and poppler (minimal example)

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minimal working example, which creates a GTK-window and displays the first page of the given pdf-file.(compile with command: gcc example.c -o example `pkg-config –cflags –libs gtk+-3.0 poppler poppler-glib`) versions: GTK+ 3.24.23-2 and poppler-20.09.0-2

[Howto] GTK+ and cairo (minimal example)

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minimal working example, which creates a GTK-drawing-area and draws ‘Test.’ inside.(compile with command: gcc example.c -o example `pkg-config –cflags –libs gtk+-3.0`) versions: GTK+ 3.24.23-2 and cairo 1.16.0-4

[FAQ] QElectroTech

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Q: How to show power-contacts in contact-table?A: menu “project” –> menu-entry “project-properties” –> Tab “new folio” –> Tab “cross-references” –> type-entry “coil” –> enable “show the power contacts in the cross” Q: What is the difference between “label formula” and … Continued

[Howto] OpenBox – default to maximized windows

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The following configuration let openbox open all windows maximized per default: edit ~/.config/openbox/rc.xml and insert in the <applications>-tags: reconfigure running openbox (Desktop –> rightclick –> reconfigure) or restart openbox. Now all applications open in maximized windows. further informations: http://openbox.org/wiki/Help:Applications If … Continued

[Howto] GTK3 with CSS (minimal example)

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It is a working example for a button, which changes its color while mouse-over. gtk-version:   3.24.12-1 note:  the css-property “background-image: none” is sometimes mandatory, because the default theme prevents displaying the css-defined background-color. The workaround is to set the … Continued