Tag Archives: CPU

Are Today’s MCUs Overdesigned? A Research Team Has The Answer

MCUs are called microcontrollers because they embed a CPU, memory and I/O units in one package. Apparently, today’s MCUs are full of peripherals and in most cases they are not used in the application, and from an engineering point of view this is a waste of money and energy, but on the other hand, for developers and consumers it’s about programmability and flexibility.

Rakesh Kumar a University of Illinois electrical and computer engineering professor and John Sartori a University of Minnesota assistant professor tried to prove that processors are overdesigned for most applications.

Kumar and his colleagues did 15 ordinary MCU applications using openMSP430 microcontroller with bare metal and RTOS approach (both are tested in their study). Surprisingly, the results showed that all of these applications needed no more than 60 percent of the gates. Therefore, smaller MCUs can be used (cheaper and less power consuming). As stated by Sartori, “a lot of logic that can be completely eliminated, and the software still works perfectly”.

Bespoke Processor research results
Image courtesy by: University of Illinois/ACM

In the image above the analysis of unused gates for two applications: Interpolation FIR filter and Scrambled Interpolation FIR. The red dots are the used gates and gray ones are the not used ones.

The research team called the optimum MCU the “Bespoke Processor”, and described the process “like a black box. Input the app, and it outputs the processor design.” says Kumar.

Source: IEEE Spectrum

Inside the vintage 74181 ALU chip

Ken Shirriff writes:

The 74181 ALU (arithmetic/logic unit) chip powered many of the minicomputers of the 1970s: it provided fast 4-bit arithmetic and logic functions, and could be combined to handle larger words, making it a key part of many CPUs.

Inside the vintage 74181 ALU chip – [Link]

Tiny OLED PC Performance Monitor

p1090014-large

Rupert Hirst build a tiny OLED PC performance monitor based on Psyrax’s serial monitor. The display monitors CPU and GPU temperature and activity etc. He writes:

After a recent purchase of a Nvidia GTX1080 graphics card, 4k monitor plus Doom(2016), I thought it would be great to see some external telemetry… from my exorbitant purchase.
Then, I Stumbled upon on Psyrax’s “Serialmonitor” GitHub repository! Armed with an Arduino ProMicro plus a 128×64 pixel OLED display, I compiled the source code. After compiling Psyrax’s windows application in Visual Studio, I got to work.

Tiny OLED PC Performance Monitor – [Link]

A Bench Power Supply using computer PSU

As we know, PSU in computers provides various DC voltages, 3.3V, 5V and 12V. These 3 levels are the most common ones needed in our labs, so usually PC PSUs are used by a lot of makers and hackers as their personal bench power supply. The PSU has a standard connector called ATX, you can reach all of the voltages levels using it.

[Supercap2F] hacked his own PSU into a bench power supply and published the project details. Supercap2F’s power supply design include:

  • PIC18F1220.
  • 16*02 LCD as a user interface.
  • Three switches for user control (select/move).
  • Relays controlled by PIC18F1220 to switch outputs on/off.
  • Fused Outputs: +3.3V, +5V, +12V and -12V.

SchematicPSU

[Supercap2F] published the circuit designs (PCB&SCH) and source code for PIC18F1220 over Github.

front-acover

Via: Hackaday

What Will Happen to Moore’s Law in 2021?

Moore’s law states that the number of transistors doubles every two years. Rachel Courtland from IEEE Spectrum explained the sharp turn of Moore’s law in 2021.

Moore2021Chip manufactures will switch to another way of boosting the density in the chip by having multilayer chips using vertical geometry, and we’ve already seen the 3D concept in silicon chips like 3D NAND Flash. According to 2015 roadmap released by International Technology Roadmap for Semiconductors (ITRS), by 2021, shrinking the dimensions of transistors in microprocessors will not be desired economically by chip makers, although the report of 2014 predicted that the physical dimensions would continue to shrink until at least 2028.

According to the article, the spirit of Moore’s Law could still there, where some changes in the technologies will still lead to pack more transistors in a given area.

Rachel also mentioned  that first international Rebooting Computing conference will be held in October this year 2016. It’s “Other ITRS participants are expected to continue on with a new roadmapping effort under a new name” Rachel said.

[Article on IEEE Spectrum]

Schematic, Mask, and Die Shot of Intel’s 4004 CPU from 1971

Intel_C4004

Celebrating its 45th anniversary, adafruit stumbled upon these high-resolution images of Intel’s 1971-released 4004 CPU. Click any of the below images to view them at their maximum scale on the MIT domain:

Schematic, Mask, and Die Shot of Intel’s 4004 CPU from 1971 – [Link]

All CPU and MCU documentation in one place

cpu_list

larsbrinkhoff @ github.com has compiled a list of all CPU and MCU documentation. The list contains data sheets, programmer’s manuals, quick reference cards etc.

This repository contains the documentations for various CPUs. It may contain data sheets, programmer’s manuals, quick reference cards, and the like.

All CPU and MCU documentation in one place – [Link]