voltage and current

-
voltage: force responsible for movement of electrons(electric current) through a electric circuit
current:amount of electrons flowing at a point per second

Comments

Post a Comment

Popular posts from this blog

bb.utils.contains yocto

-
Image
bb.utils.contains  is most commonly used function in Yocto. grep in poky directory returned with 696 count. $ grep -nr 'bb.utils.contains' poky/ | wc -l 696 It's definition is present in 'poky/bitbake/lib/bb/utils.py' file This function returns third argument if the second argument is subset of the first argument else returns fourth argument Let's take an example to understand this. You can see from the above screenshot, when the second argument is a subset of first argument, "present" was returned, else "notpresent" was returned We can also use bb.utils.contains inside if loop. This we can use inside a recipe. if ${@bb.utils.contains('SOMEFLAG','NEWVALUE3','true','false',d)}; then     FOO = 'HELLO' fi
Read more

Connecting Serial ports of two Ubuntu VMWare Virtual Machines

-
Image
This post is to establish the serial communication between two Virtual Machines running Ubuntu in VMWare. Serial Ports are very important and with this setup, we can write applications and don't worry to have a hardware. This setup is also used if we need to setup KGDB Steps on the First Virtual Machine: Step1: Open Virtual Machine Settings and click on Add Step2:  Select "Serial Port" and Click On Next Step3: Select "Use Named Pipe" Step4: You will observe the named pipe of the form \\.\pipe\<namedpipe>. Keep the settings as it is i..e, the named pipe: \\.\pipe\com_1 ( it will be ttyS1 in Linux) and click on Finish Steps on the Second Virtual Machine: Perform the same steps  1 to 4 except in 4th step select "This end is Client". Testing the serial connection between VMs: 1. Power on the two VMs 2. On First VM : cat /dev/ttyS1 and the other VM: echo "hello" > /dev/ttyS1
Read more

make config vs oldconfig vs defconfig vs menuconfig vs savedefconfig

-
Image
Building the Linux Kernel is a two-step process: Configuring the Kernel options Building the Kernel with those options. There are many methods available for configuring the kernel. make config: Text-based Configuration.  Options are prompted one after another. All options need to be answered Access to former options is not possible make menuconfig: Menu-driven user interface Allows to navigate forwards and backward directly between features Allows to load and save files with filenames different from ".config" Provides search feature It uses ncurses library for GUI. If the ncurses library is not installed, make menuconfig option fails. To install ncurses library on Ubuntu: sudo apt-get install libncurses5-dev make defconfig: Creates a ".config" file with default options from the ARCH supplied defconfig Configurations are generally stored in the directory: arch/$(ARCH)/configs $ ls arch/x86/configs/ i386_defconfi...
Read more