Questions tagged [register]

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

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Capturing x86 register value changes in hardware i.e. at circuit level

I need to find a way of observing (on another 'monitor' machine) changes to registers critical to the address translation process on x86 platforms - including IDTR, GDTR, CR3, etc. This monitoring ...
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Confusion between register size, address size, data size

I started learning about pointers in C++ and I figured I should educate myself a bit on how memory works and is accessed. I read that when we say a processor is 64-bit, it has a 64-bit register and ...
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508 views

8-bit Serial I/O Parallel I/O Bi-Directional Shift Register [closed]

I am looking for a register that has as stated Serial In Parallel Out and Parallel In Serial Out modes and bi-directional shift functionality all in one IC. I want to use it with Arduino. Does ...
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37 views

project RT level using register [closed]

to every one. excuse my poor english. may someone help me resolve this problem. What does RT level means? A,B,C,D,W,X,Y and Z are register of n bit. project the RT level of this function just using on ...
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PCB testing register software [closed]

Good day all, This is my first question on the electronics board, and I have checked for similar queries, but so far no luck. It is possible that I'm searching for the wrong terms, so I will ...
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809 views

Why are Index Registers needed?

In a cpu, why are/were Index Registers needed? You can of course live without them, but why would you want them? Wikipedia says that they are used for vector/array operations, but I'm not really sure ...
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783 views

Writing MIPS assembly and machine code for instructions

I am continuing my practice with MIPS assembly and machine code. I am doing a problem that assumes the following: ...
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1answer
3k views

MIPS assembly instruction to machine code in hex

I am doing some practice problems involving MIPS assembly instructions and machine code(in hex). I am doing a problem but am uncertain if it is correct. This is the problem, and what I did: ...
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1answer
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4-bit Register with Four Operations

I'm given a task to design a 4-bit register using D Flip-Flops (and MUXes) that operates according to the following selection inputs: When.. S1S0 = 00, No Change; S1S0 = 01, Register is Cleared to ...
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accumulator using 74hc194

I need help, I want make circuit that will load or store data from accumulator to another register. I have attached circuit I am not sure that diagram will work?
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1answer
744 views

VHDL code and unintended latches

I am working on coding a Regsiter a1 with input signals b1,rst and wra1 the register ...
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5k views

Determining memory address width from memory size

Given a computer A with 1024 x 16 memory and a computer B with 16K x 32 memory, how big are the registers of an Accumulator, program counter, instruction, temporary register, address register, data ...
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1answer
628 views

implementing direct addressing mode for a load instruction on a mips archtitecture

Given a Mips machine with 26 bit addresses and 32 bits data-paths, where the load instruction is as follows |OPT code|rs|rd|immediate| |6 bits |5 bits|5 bits|16 bits| The OPT code is the ...
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1answer
762 views

Verilog only assigns first bit of a bus

I'm trying to assign a 12bit parallel bus to a 12bit register. I've reduced the problem to this literal assignment but as with the previous case, only the first bit is being written to anything when ...
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1answer
273 views

Signed to unsigned for registers

I have just started to program some code at the lower levels. I have been told to change any signed integers into unsigned integers and store these in the HW registers. I have done this OK but I am ...
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2answers
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How to change reg in two different always blocks?

How can I change/alter a register's value in two different always blocks for synthesizeability? For example: ...
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682 views

Register Syntax question

I was reading some code to use an on an arduino ATMEGA328P and I can't figure out what this line of code does. ASSR &= ~(_BV(EXCLK) | _BV(AS2)); I know that ...
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8080 assembly comparing which of the numbers is greater etc

In my 8080 assembly project I need to check if user entered digits and if so do some stuff on it, otherwise display some error and close app. Normally i would do it like that ...
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1answer
669 views

Trying to start i2c communication on dspic33fj128gp802, but I cannot write on the SEN bit of the I2CxCON register

Good evening, I was trying to start the communication with the I2C on my pic. I only set the bits in the control register in the code for now and the inizialization of both the pins and the PLL, and I ...
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2answers
1k views

register without clk

I'm designing a small system in VHDL using the datapath and contorller method. Is it okay if I design registers that don't have a clock input (load data on the rising edge of the load signal) as they ...
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2answers
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Problem in writing register maps using C structure for a TI Microcontroller

I am writing register maps in C for a TI ARM based Micro-controller board. Here is the link to the datasheet. I am using the following guidelines on how Register maps should be written in C: ...
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1answer
533 views

MSP430 RAM protection

I'm looking at the user guide for the MSP430x5xx family. It says there in section 9.1 that: ...
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2answers
5k views

Setup Time, Hold Time - What is the underlying principle for having them?

I'm learning about setup time and hold time of a FF connected to a bus. But the textbook fails to explain exactly why are those needed in an operation. Isn't a FF always powered on and attentive to ...
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47k views

What is the difference between registers, flip flops and latches?

I want the answer to the very basic level. I know what they mean individually, but what I am looking for is connection between them.
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1answer
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Clearing Flag Bits By Writing 1

Most of the interface devices have various flag bits (that can also raise interrupts if that functionality is provided) used to check the status of the device/operation. Usually they are cleared by ...
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1answer
450 views

Configure GPIO pin for infrared interface (IRTIM) of STM32F030x4/x6/x8

I have a problem for use infrared interface (IRTIM) of my MCU. When I saw in Reference manual I could find this: Now, when I search for find GPIOx_AFRx register, I cannot find this register in ...
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1answer
568 views

Eliminating Signal Race Hazard in an IC dynamic latch/register!

I work in MAGIC Integrated Circuit software at layout-level. I got an 8bit dynamic register made of 1bit dynamic flipflops that write input on the positive edge of the signal: (Note: I used ...
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1answer
366 views

how the CPU start by execution stored in motherboards flash memory chip [closed]

I had read that at start, the CPU program counter register is fill with F000. I though that: PC registers contain the next instruction address. This address is send to the address bus and value ...
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1answer
888 views

Integrated Circuit Layout Design - Dynamic Flip Flop?

I need to create a dynamic flip flop like this: In integrated circuit technology, at mask layout level. I then want to create an 8bit register, using 8 of these flip flops, with a common CLK signal. ...
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1answer
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What does banking mean when applied to registers?

This answer to a question on StackOverflow about what banking means in the context of ARM's banked registers indicates that there is some confusion about the meaning of banking when applied to ...
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2answers
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How to design a left shift register

I want a circuit in which I get the following sequence: 0001, 0010, 0100, 1000, 0001 I know that it's 4-bit shift register. But what is my approach to design ...
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1answer
188 views

How data movement from large register to small register works in VHDL?

I went through a VHDL sample code for memory management. In that data from a 32 bit register was directly moved into a 8 bit register. My doubt it is how this data movement can happen? Is there is any ...
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2answers
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How many servos can I run on an ATtiny85?

This is my first time asking a question on this website, so please correct me if I'm doing something wrong... I have been working on a small project which runs three Servo motors on an ATtiny85, ...
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VHDL: How to double read a register bank?

We have been tasked with creating a register bank that can dual read, but only single write. At the moment I've got it all working apart from the dual read. Could someone point me in the right ...
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STM32F0 GPIOx_ODR vs GPIOx_BSRR

Apart from the register structure what is the difference between GPIOx_ODR and GPIOx_BSRR? Is GPIOx_BSRR an abstraction layer for GPIOx_ODR? I know that a change in GPIOx_BSRR "will" change the ...
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914 views

How to clear a 4 bit shift register with no clear input?

I have 4 bit pipo shift register 74ls95 . It does not have an clear input. Is there any way to clear the register without giving all the parallel inputs as zero. I am using it as an component of shift ...
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A program to add 6 bytes of data and store sum and carry in 8085 instruction set

I have a question on 8085 instruction set. A program to add 6 bytes of data stored in memory starting from 4500h. must use b register to save any carries and finally store the sum and carry at two ...
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Clocked edge-triggered timing (contamination delay)

I'm reading a book about computer architecture, and it says that, in clocked edge-triggered devices, the contamination delay is usually nonzero, and that the contamination delay for registers is ...
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2answers
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What is the difference between TCCR1A and TCCR1B [closed]

I had an error in the configuration of PWM for the atmega8 because I didn't set my register properly. But I thought that Timer 1 is timer 1, no matter is TCCR1A or TCCR1B. Why can I set all the timer ...
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1answer
895 views

What is the purpose of CRC_IDR in STM32 processors?

The STM32's CRC calculation unit has a register named CRC_IDR. This 32 bit register allows the user to store 8bits of data. There seems to be no link between this register and rest of the CRC ...
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How to avoid input/output conflicts with a bus

How does a system bus work? I don't understand how can a circuit avoid input/output issues with a bus. I included an image to better explain my thinking. The circuit has 2 general purpose registers ...
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Veriog:How to pass a register to a module?

Assume we have a module with 32 bits output like this: module ModuleLow(foo,...); output [31:0] foo; Now we want to use it in another module ( a very simple ...
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1answer
173 views

AVR registers location

There are four types of registers in AVR. \$r_0\$ - \$r_{15}\$ witch used for CPU's calculations. \$r_{16}\$ - \$r_{31}\$ witch used for user's temporary data storage. Registers for I/O statements. ...
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What actually is a shadow register?

I noticed the term Shadow Register while going through a datasheet of a TMS320F28335 DSP. What does it actually mean? Does it have a physical location in the CPU as ...
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1answer
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Difference between a n bit Latch and a buffer

What is the difference between a 8 bit buffer and a 8 bit latch? Are they both used for the same purpose? The 74LS273, is a buffer or a latch?
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How does register type modifier work on different CPU architectures?

This question is to clarify my doubt against this register storage class. when a variable is register qualified ,compiler puts the variable in a cpu register other than RAM for ease of access. so ...
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401 views

How does a 8 bit register bank hold 8 regsiters of 8 bits each?

In 8051, there are 128 bytes of RAM. Of which, 32 are set aside for registers in the form of banks, 8 registers to each bank. ...
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Is it possible to exchange the content of two registers in a single clock pulse?

There are two register R1 and R2. How is it possible to exchange the content of R1 and R2 in a single clock pulse using Common bus architecture?
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Why are bitfields in register not sequential?

Why are the bit-fields in the register not sequential? For example, consider an 8 bit register X . X will have bits 0-2 with flags and 3-6 may be reserved and bit 7 may again represent some flag. Why ...
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Registers & Buses

My task is to design a schematic for a register that has an input of clk and i[7:0] which is an 8 bit binary input interpreted as a number and an output of F which goes high if i was equal was to 127 ...