#hotplug

Flex Slot Power Supply Kit for ProLiant G9-G10

Fastboot – no permissions (missing udev rules? user is in the plugdev group)

When we put our device to fastboot mode for flashing our binaries using fastboot command, while trying to check if device is connect or not using “fastboot devices” command, we got below error, $ fastboot devices no permissions (missing udev rules? user is in the plugdev group); see [http://developer.android.com/tools/device.html] fastboot We could always use “sudo fastboot devices” but this is…

Raspberry Pi – How to Use the Pi on a VGA Monitor

This post is to get your Raspberry Pi to work through a computer monitor using a VGA lead in case you don’t have access to a TV with HDMI port.

You will need:

HDMI to VGA adapter – This can be bought cheap (£5), mine was from Amazon UK – Click Here to see Amazon’s Adapter –

You will need a VGA cable which can be bought for less than £1 in some places.

Micro SD Card Reader – such as a  ‘USB Micro…

Resolved: How to configure `eth0` to retry `dhclient` when unplugged and replugged? #answer #development #dev

How to configure `eth0` to retry `dhclient` when unplugged and replugged?

I’m working on a linux gadget.

I want it to get DHCP if I plug in the network cable after it has booted up already or if the network cable unplugged and replugged.

One solution is to run a script such as this (which works, btw):

#!/bin/bash NET_STATUS='different' while true do NEW_NET_STATUS=`ifconfig | grep RUNNING | grep…

In the previous post we polled the PS2 controller for whichever data it would provide, but we can get more out of it. I'm particularly interested in the rumble motors: we could get feedback without having to look at LEDs or a screen.

The PS2 controller supports different commands. We previously relied on a single command: poll (0x42). To access the advanced features we have to send other commands. Curious Inventor lists them all.

I first tried to force the controller into analog mode as it looked easier than configuring the rumble motors: we have to send "enter config" (0x43), then "enable analog mode" (0x44), and finally "exit config" (0x43). I significantly reworked the library to support arbitrary commands. In the process I discovered that my earlier estimate for the delay between frames (15-20us) was seriously underestimated: 4ms seems to yield much better results. Shorter delays may result in a 3rd byte of the header response that is different from the expected 0x5a. I believe the other values I encountered (0x00, 0xff, 0xfe) might be error codes but I did not investigate further.

It started as a simple test but forcing the controller into analog mode is actually a nice feature. We don't have to worry about the mode: we can just read the analog sticks whenever. Configuring the controller at the beginning of the sketch works well, but problems may arise if it gets disconnected/reconnected or if the mode changes for other unforeseen reasons. In order to address this I added a counter to reconfigure the controller on a regular basis. I preferred this strategy to reconfiguring only if the mode was not analog: I didn't want to make too many assumptions on the problems which might arise.

At this stage adding support for the rumble motors is trivial. We just need to call "enable rumble" (0x4d) during our configuration sequence and map the motors to the first 2 bytes transmitted to the controller during the poll command (0x42). This requires a minor change to the poll() function and adding 2 functions to control a motor each. I also updated the sketch so that the X and O buttons would make the gamepad vibrate.

The implementation uses a lot of delays, one of which blocks the microcontroller for 4ms at a time. This is inefficient and we may want to run other code while the gamepad is getting ready. I divided the configuration sequence in different states and implemented them as a finite-state machine. Each call to update() checks that enough time has elapsed and runs the next command in the sequence according to the following flowchart.

Is it possible to hot plug an external HDD via eSata?

Entry (Optional Reading).

I have long been using eSata connector, but I realized that I’ve had enough. And all because of the fact that 1) it can not be connected to the hot 2) If the external HDD is disabled, the BIOS will be initialized exactly 1 minute longer, stubbornly trying to interview these same eSata ports (what for, if the drive is turned off?) 3) a complete shutdown eSata support in…