Questions tagged [register]

A special, high-speed storage area within the CPU.

Filter by
Sorted by
Tagged with
4
votes
2answers
3k views

How can a shift register be used to debounce a switch?

This is the problem: This is the proposed solution: What I don't understand: The button bounces in the setup/hold time of the input of the circuit, making the FF go into a metastable state whereby ...
2
votes
4answers
2k views

What is important in computer clocks' signal: signal edges or intervals when signal is stable? Will multiple value propagation occur?

I am trying to figure out some basics of digital electronics. We have all seen the squared graph of the computer clock signal: I have read multiple articles on the Internet and still can't figure out ...
2
votes
2answers
3k views

What is the meaning of "Register.Rd"?

Reading Hennessy's book "Computer Organization and Design" it is mentioned "Register.Rd" and "Register.Rs" but what does it mean? The .Rd, .Rt and .Rs parts I can't understand, on page 365:
0
votes
1answer
222 views

How can a simple operation such as moving data from one register to another can be encoded into an instruction and executed in a single clock cycle.? [closed]

The simple point I'm trying to make for an essay Im writing. I'm completely at a loss as to how to answer this. Any help available? Sorry, I know this is not a well formed question but I've got no ...
0
votes
1answer
157 views

Shifting between PWM options

I'm using a Freescale MC9S08DZ60 microcontroller, and Ive written the code for applying PWM on a specific pin.'This is an attempt for Breathing Effect of LED, a question i had already asked - LED ...
6
votes
1answer
4k views

Converting AVR assembly to machine code - addressing registers?

In AVR Assembly - I want to work out the machine code representation of the following: ANDI r18,$10 I know the opcode for ANDI is ...
3
votes
2answers
1k views

What does register and bus size depend on?

So here is a hardware sequential multiplier depicted. Number A is 51 bits width, number B is 48 bits width. I have to choose the most efficient size of buses and registers (optimize according to ...
7
votes
9answers
7k views

Microprocessors/Microcontrollers - Do registers have addresses?

My Embedded Systems professor keeps referring to the memory locations of registers as their respective "addresses". I'm confused by this; I was always under the impression that in any microprocessor, ...
5
votes
3answers
4k views

What is the underlying mechanism behind RO or WO and WR registers?

In embedded systems you have read only and write only registers. How are the two type distinguished in the produced netlist? How one builds a flop which you can only write to and not read from?
0
votes
1answer
14k views

What does the "Q" in "Clock-to-Q delay" stand for? [duplicate]

Possible Duplicate: Why is the output of stateful elements often named Q? A register has D (data) as input and Q as output. What does the Q stand for? I'm having a hard time searching for it.
3
votes
3answers
2k views

Can I pass a bit register as a function argument in Hi-Tech C compiler for PIC16?

Is there a way to pass a bit from a PIC's register as a function parameter? Taking, for example, the PIC16F887, its registers (SFRs) and individual bits are defined as fallows in the corresponding ...
2
votes
1answer
3k views

Access Register/signal from Multiple Modules (Shared Memory)

I want to implement a data register to store up to 256 8 bit chunks (VHDL). I also need to to be able to access and modify these values from multiple vhdl modules. One module will access the register ...
2
votes
2answers
2k views

Verilog asynchronous reads of regs - and design question

I'm trying to understand what the following bit of behavioral code, what kind of hardware it turns into: ...
3
votes
3answers
2k views

Understanding Flip Flops/Registers in Low Level

So I'm reading "Elements of Computing Systems" trying to really understand how everything works underneath (Any other book/article suggestions that would help would be amazing) Since eventually I want ...
1
vote
2answers
231 views

Data transfer between FFs in a CPU

I was in computer organization lecture and when we wrote what the CPU does during an add instruction (like micro instructions) something got me thinking. I didn't understand how we let one of the FFs ...
0
votes
1answer
129 views

4 Bit Register not loading properly

Basically I have a 4 Bit Shift Register that I am trying to get to work. From my understanding when I send a pulse of 1-1 to inputs S0 and S1..it is suppose to do a parallel load. I have ensured that ...
6
votes
5answers
1k views

stack cache instead of registers

Is there a processor that do arithmetic operations on a stack and not on registers? To keep performance, of course, that processor should cache top block of a stack in the same type of memory that is ...
5
votes
3answers
5k views

What is the main difference between registers, bit fields, and flags?

In school I was accustomed to programming various registers when working with microcontrollers to manipulate their behavior. At my job registers are now referred to purely as bit fields. The word "...
5
votes
1answer
844 views

One-clock increment operation in a three-bus CPU architecture

In his chapter on CPU design, Edward Bosworth introduces the following three-bus architecture: One of the main design aims of this circuit is to be able to increment the program counter PC in a ...
0
votes
1answer
301 views

Store frequency value

I'm not much of an "electrical engineer" but the required courses in my CS degree have given me enough to [albeit just barely] understand a few things, so don't judge me if what I ask is complete ...
10
votes
3answers
7k views

Do AVR registers and ports need to be initialized to zero?

During the initialization routine of my code I use to do such things as: clr r0 ; will always stay zero and: ...
3
votes
2answers
1k views

early accumulator based machines

Wikipedia says that many of the early machines were accumulator-based machines. My guess is that in those machines the accumulator did not play the role of a speed-up register as do registers in today ...
1
vote
2answers
990 views

Lighting 128 LEDs from shift registers

My question is on lighting 128 LED's from shift registers. I had originally considered using a string of 16 74HC595's but upon further research, it appears they would not supply enough current to ...
3
votes
2answers
9k views

How do I select what values to load in CCPR1L register (for generating PWM signal with PIC)?

I need to generate PWM signal with PIC18F2550 microcontroller at near 20kHz. I read the datasheet, I found it too complex and confusing, then I started to search for a sample code on the net to ...
2
votes
3answers
1k views

what happens when the carry bit is zero in addition/subtraction algo for hardware

This is the algorithm in flow diagram for addition and subtraction in computers. A(s) is the sign bit of A B(s) is the sign bit of B //(s) denotes the subscript E is the register that has a carry ...

1 2 3 4 5
6