Counting bits in hardware: Reverse engineering the silicon in the ARM1 processor

From freeio.org 6 years ago in Blogs Platforms

Ken Shirriff writes: How can you count bits in hardware? In this article, I reverse-engineer the circuit used by the ARM1 processor to count the number of set bits in a 16-bit field, showing how individual transistors form multiplexers, which … Read more

Articles from FreeIO

M2 by Macchina joins At Heart!

From freeio.org 5 years ago in Blogs Platforms

We’re excited to announce the latest member of Arduino’s AtHeart program. M2 by Macchina–now live on Kickstarter–is an open-source, versatile development platform for hacking and customizing cars. M2’s design is compact, modular, wirelessly connectable, and built on the popular Arduino Due. The...

Cassette deck in an old Ferrari, Pi-fied

From freeio.org 5 years ago in Blogs Platforms

Here’s one for the classic car enthusiasts and audiophiles in the room. Matthew Leigh (Managing Director of Infomagnet by day, skilled maker by night) took the aged cassette deck from an old Ferarri, and brought it into 2017 with the help...

Teardown and analysis of microwave (26.5GHz) electro-mechanical step attenuators

From freeio.org 5 years ago in Blogs Platforms

Teardown and analysis of microwave (26.5GHz) electro-mechanical step attenuators from The Signal Path: In this short episode Shahriar takes a close look at a pair of Hewlett Packard microwave electro-mechanical step attenuators operating up to 26.5GHz. Mechanical attenuators offer excellent...

DIY laser scanning microscope

From freeio.org 5 years ago in Blogs Platforms

Venkes shared detailed instructions of how to make a DIY Laser Scanning Microscope (LSM): The reason I was thinking of a DVD pick-up is that it houses a laser and a lens capable of projecting a spot of visible laser...

Make sure guests never miss your house with these numbers

From freeio.org 5 years ago in Blogs Platforms

If you’d like for someone to visit you, it’s quite helpful if you have the house number displayed somewhere on your premises. Rather than simply rely upon someone reading the numbers as they drove by, “Superbender” has decided to do something a bit different...

Adventures in Science: How to Use Calipers

From freeio.org 5 years ago in Blogs Platforms

Based on a suggestion by user Sembazuru, we made a video showing you how to use calipers! Digital calipers are fairly straightforward, but it can be a little tricky to read dial and Vernier calipers. Don’t worry; we’ve got you...

BlackMagicProbe SMDprutser style

From freeio.org 5 years ago in Blogs Platforms

Sjaak has published a new build: When you get started on ARM microcontrollers things are very overwhelming at first… After coping with the first few hurdles like installing a toolchain and IDE, the next part should be getting a tool...

Cambridge theme for PIXEL

From freeio.org 5 years ago in Blogs Platforms

Raspberry Pi is based in Cambridge. (Just to be clear, that’s the one in East Anglia, UK, not the one in Massachusetts, USA.) When we say “based in Cambridge”, that suggests (correctly) that our offices are here. But the connection...

Free PCB Sunday: Pick your PCB

From freeio.org 5 years ago in Blogs Platforms

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our...

App note: Charging batteries using USB power

From freeio.org 5 years ago in Blogs Platforms

Fairly old application note from MAXIM Integrated about getting out power from USB ports. Link here (PDF) Many devices with rechargeable batteries use USB power to recharge the batteries while they are connected. This application note describes the power available...