Low-Power | Low Power Library for Arduino

I am working with a DragonBoard 410C using Android 5.1 and Kotlin to experiment with the GPIO pins on the 40 pin low power connector. The library I'm using is using the sysfs interface for interacting with the GPIO pins which requires opening various pseudo files in /sys/class/gpio/ directory tree and reading and writing values to those files, see accessing GPIO low power connector on DragonBoard 410C running Android

My understanding is that I can provision a GPIO pin as Input and Edge triggered which would allow me to wire up a simple circuit with a momentary contact switch and be able to detect when the switch is pressed.

However the documentation I've found indicates that I need to use the poll(2) system service or the select(2) system service on a file descriptor for the /value pseudo file of the GPIO pin I am using in order to detect when the Edge is detected, e.g. /sys/class/gpio/gpio910/value.

How do I use the poll(2) or select(2) system services with a file descriptor in Kotlin? Is poll(2) the same as ready() method of FileReader?

Perhaps something similar to the Java WatchService functionality is needed? http://www.java2s.com/Tutorials/Java/java.nio.file/WatchService/0060__WatchService.poll_.htm

What I am planning, unless this is the wrong approach, is to have a utility function, something like:

I am using PIC16F18875 and XC8 compiler. I am using PPS for the first time. I have configure the UART but it is not working propely. Frequency is 8MHz. i have set input PPS and Output PPS mode.

i try to setup the LPSTK-CC1352R Launchpad with Node RED and a bluetooth connection. the inbuild sensor is a hdc2080 sensor. I'm not a electronic engineer so the datasheets are a bit confusing to me. I made it to the point, where i have a connection to the MCU via bluetooth and get every second the temperature values. Unfortunately i get these values as a 4 dimensional hex array.

How does a hypothetical OS kernel on a MIPS I compliant CPU actually implement a syscall 10, thus halting all execution, and power down?

The long story:

I'm currently building a MIPS emulator, based specifically on the MIPS I architecture specification; I have dealt with (almost) the whole ISA that comes with it, and made some deep and interesting discoveries along the way. I'm also dabbling on the privileged resources, and anything involving the system coprocessor (COP0).

I am intent on writing a basic kernel that handles exceptions/syscalls/traps in a privileged context, mostly to simulate how syscalls are executed from a kernel-mode standpoint; one that is currently stumping me is the termination syscall, code 10. I expected to find some (privileged) instruction that does halt execution like HLT does to x86; however the closest thing to it I can find is the WAIT instruction.

WAIT is actually designed to switch the CPU to low-power mode and wait for interrupts, and is found in the ISA, therefore making it available in user mode too; there is no indication of terminating execution, although I could figure out some way to fabricate it from this.

However; I feel that I'm on a wrong track, and the volumes I-A, II-A and III of the MIPS specification are not helping me much anymore. To put it in other words: does somebody know what actually goes on in a real MIPS CPU after a syscall 10 is executed?

I am creating a php script to scrape the images and respective dimension recommendations from https://gtmetrix.com/reports/example.com/a_unique_code.

After extracting the image path and the suggested new height and width, I will programmatically optimize my images.

The following is the relevant portion of the html returned from the Uniform Resource Locator:

I'm trying to port a project from Cortex M0 to Cortex M4 with hardware floating point extension, the new target soc is nRF52832.

The error I am getting from the linker is the following

I need to communicate with an already connected (paired) device attached to my computer via JavaScript.

This is a Bluetooth device however it does NOT use 'low power technology' thus is currently inaccessible via WebBluetooth.

Is there any way to communicate with my device using a different method due to the fact that it is already paired with the computer? Maybe as some sort of serial connection?

Targeting support for Google Chrome.

Node.js or anything outside the realm of HTML5/JavaScript/Chrome Specific JavaScript will not be accepted as an answer. WebBluetooth already shows an example however my device does not use Low-Power-Bluetooth..

I have implemented a device driver for the NRF24L01+ transceiver in userspace using rust. The userspace driver makes use of the kernel spi interface driver. Writing the driver as kernel module seems incredibly hard, as the documentation for linux/netdevice.h as found in linux device drivers seems outdated (or I'm just not smart enough to understand the intricate details).

A new project from the TU Munich proposes the use of vfio. From my understanding this type of driver implementation uses the iommu to manage isolation to protected memory areas for the devices. "Project Ixy" uses the network device as block device, hence it can be mapped. SPI is different as insofar it is a streaming protocol.

My question is, if it is possible to integrate the user space spi network device driver into the linux network stack, e.g. having all protocols etc handled by the network stack. Is it possible to use a similar approach as Project Ixy, like having a small component in kernel space, which is isolated for security, that builds a "bridge" to userland?

I have a real stumper I've been stuck on for a while. I am programming a PIC16F15376 microcontroller Xpress board in C.

I initialize a volatile variable called buttonIntention to 0. When the interrupt service routine occurs, buttonSet(1) is called, effectively setting buttonIntention = 1. [Note: I have also tried just toggling the buttonIntention variable directly, with no get or set functions.] In main(), the while(1) that is constantly polling checks whether the ISR has gone off (which would set buttonIntention = 1) and if the ISR did, the TESTPIN is set high where I can view it on my o-scope.

I have determined that when I pressed a button, the ISR does indeed fire. buttonIntention is then set to 1 within the ISR, because the commented out code at the end of the ISR I tried works fine.

However, my if(buttonIntention) in my while(1) in main() never actually sees buttonIntention set to 1. I thought having this variable as volatile would fix this issue because it is shared between the ISR and main(), and I thought using a uint8_t type on my 8-bit microcontroller would fix any "atomic" issues I have read about but don't really understand... but, there's still something wrong that the if statement never sees a 1.

Any ideas?

Here is my code: