I just finished taking an embedded systems course that was mainly centered around software. We used an ARM processor throughout the semester and our professor drew a simplified circuit diagram of a processor. I’ve attached the picture below. Because the course was software focused, we didn’t go beyond a quick explanation of how this simplified processor would work.
What additional components would a complete version of this circuit contain?
Also, wouldn’t the demultiplexer output 0 to all outputs except for the selected register (Rd) in this diagram? Is some of the logic excluded for simplicity, or am I misunderstanding something?
Not really my best area, however the arduino due uses a version of the arm that doesnt need much extra to run, the board has a voltage reg and a usb to serial converter thats about it, and you could depending on what device you were buiding even make a board without those.
A microcontroller usually has everything on board to run software, rom, ram, gpio, serial etc.
Not really my best area, however the arduino due uses a version of the arm that doesnt need much extra to run, the board has a voltage reg and a usb to serial converter thats about it, and you could depending on what device you were buiding even make a board without those.
A microcontroller usually has everything on board to run software, rom, ram, gpio, serial etc.
The Arduino doesn't use an ARM processor. Although MicroChip/Atmel do manufacturer ARM processors under licence.
The tiny part of circuit in the OP seems pretty meaningless, it's not a 'simplified' processor, but merely a tiny part of one.
For the OP - I would completely ignore the 'diagram', it's of no use to you (or anyone else), and presumably was only given to explain a small specific point.
The Arduino doesn't use an ARM processor. Although MicroChip/Atmel do manufacturer ARM processors under licence.
The tiny part of circuit in the OP seems pretty meaningless, it's not a 'simplified' processor, but merely a tiny part of one.
For the OP - I would completely ignore the 'diagram', it's of no use to you (or anyone else), and presumably was only given to explain a small specific point.
It was drawn to demonstrate how a processor performs actions based on machine code. If this is only a tiny part of a processor, what are the remaining parts? The diagram contains a register, control unit, and ALU. Maybe I’m mistaken, but I thought that those were the necessary parts of a processor.
Also, wouldn’t the demultiplexer output 0 to all outputs except for the selected register (Rd) in this diagram? Is some of the logic excluded for simplicity, or am I misunderstanding something?
If you call it a demux then it should, but in reality each register has an Write Enable signal, that allows the contents to be overwritten. The data lines go to all the registers in parallel, and the WE signal is then given to the appropriate one which writes the data where it belongs.
Not really my best area, however the arduino due uses a version of the arm that doesnt need much extra to run, the board has a voltage reg and a usb to serial converter thats about it, and you could depending on what device you were buiding even make a board without those.
A microcontroller usually has everything on board to run software, rom, ram, gpio, serial etc.
have a look here: https://www.bradrodriguez.com/papers/piscedu2.htm the processor described here is a very simple one made with standard TTL chips. the block diagrams on this page are a lot easier to follow. the actual schematic is here: https://www.bradrodriguez.com/papers/pisc.pdf if someone wanted to build this, they would need to do a schematic page of the power wiring for VCC and GND
On average, people know the answers to standard questions and come here for unusual cases/less obvious problems. No credit for answers that only cover "the VAST majority" of cases.
The Intel 4040 was the first microprocessor - all the main functions in a single IC
There were many non-integrated CPUs and computers prior to that, starting with electromechanical ones in the 1930s
eg. The image below the block diagram of the processor section of a PDP-8 computer, very sophisticated for its time but also simple enough to have been built with all discrete components.
It is a bit fuzzy I'm afraid, its a screen grab of a scanned page image from this site, which also contains a lot of other information and background that may be useful to the OP.
The earliest chip I've played with is the 8080a, well into the microprocessor times.
I have a couple of dekatrons similar to the harwell witch computer project.