Questions tagged [register]

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

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762 views

Make a Interrupt on a stm32f4xx

I'm new to Cortex M4 and programming on a microcontroller. I'm still learning the basics. I'm using this board (stm32f411re), here is the reference manual. I am trying to make an interrupt on the ...
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113 views

why should we have small number of registers? [closed]

I read in my book that we should have a small number of registers (such as 32 registers) What are some reasons?
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84 views

Why this concept in VHDL doesn't work?

I want to make a simple processing element for calculating the absolute difference between two 8-bit words. However, this element may be used as part of an array in order to speed up the AD ...
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1answer
261 views

Software SPI 3-wire read register

I currently try to read a register from an acceleration sensor (ADXL345). i try to simulate the SPI procedure with software. I wrote a readRegister function: ...
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1answer
95 views

Setting up a counter on STM32F405xx

How do you correctly setup Timer9 (TIM9)on an STM32F405xx to count pulses on rising edge? Is there a special configuration for the pin to the timer outside of this short example? Here's what I've ...
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1answer
247 views

Is my understanding of D-Flip Flop wrong?

So I am working on: http://www.nand2tetris.org/ and I am having a hard time understanding the D-Flip Flop, or maybe I should say, how Logism represents it. I have this circuit and this is the current ...
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2answers
3k views

8 bit-increment register with load and clear

I am quite new to design circuits topic and i have one question regarding to my assignment question. I've a simple assignment to create circuit below : I've worked on logisim to create this circuit ...
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1answer
2k views

Microcontroller memory write cycles

Information show that flash memory have a limited number of write cycles (usually ~10'000). Many MCUs emulate EEPROM in flash, hence some document this write_life_cycle. A look at any MCU datasheet ...
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4k views

Verilog Register File

I wrote a verilog code for a 4 by 9 bit register: ...
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3answers
842 views

Write to sets of two bits in a register at a time in C

I am trying to set multiple values into a 32 bit register, and each value has 2 bits. Trying to come up with an elegant way to do this. Write now I have something like this: ...
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1answer
1k views

8-Bit stereo audio R-2R DAC, is this a right way to do it?

I am new to electrical engineering and the first project I would like to do is making a digital to analog audioconverter. I've found out that a good way to do this is to use an R-2R structure for the ...
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1answer
295 views

FPGA design rules - Using a Module Output Register Value Internaly

I'm trying to optimize a verilog code and I found something that I don't feel it's correct. I found a module that has an output and it's using that output value as a condition in a case statement. ...
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352 views

P1IN Register in MSP430

Does the register P1IN has default values? I am trying to test a matrix keypad but in register P1IN-1 and P1IN2 are always high.
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1answer
550 views

PISO Shift Register using 74LS166 [closed]

I'been doing a PISO shift register using a 74LS166, but I get no results, I don't know what is happening. Here is the top view and my approach. In my approach: BLUE wire = Clear PURPLE(MARRON) = ...
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1answer
57 views

Directionable parallel in parallel out register

I have this problem. I have 3 devices that use 4bit PIPO registers to transfer each other data. I need to make the controller that select with device to use, so it will connect A with B, AC, BA, BC, ...
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1answer
414 views

What kinds of parallel RAM are there?

I have basically no experience in electrical engineering or hardware design, but as an experienced software engineer, I recently took an interest in designing my own CPU. I followed the instructions/...
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1answer
543 views

What are the addressing modes of these avr commands?

What are the addressing modes of ldi, ld, and st. I think ldi is register direct, ld is register indirect, and st is also register indirect. Are those the right addressing modes?
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1answer
379 views

Signed and unsigned registers

What is it mean when the digital code of the output of an ADC is signed? Does it have to do with application? Does it mean that the corresponding output value that is calculated is negative?
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62 views

Question about the registers of an ADC

There are two things that confuses me in the below text: "The ADC uses the successive-approximation method to perform the conversion.The HCS12 uses two 8-bit registers to hold a ananlog to digital ...
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2answers
5k views

help me to understand ANSEL register in PIC

in new to PIC,this is bit confusing. For switch ,usart we should clear ANSEL regsiter to make as digital IO so then only we can read 0 or 1 from that pin?, data sheet says if we set particular pin ...
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1answer
64 views

What do the TXRB bits do in the CiTXnDLC registers of a dsPIC 30F?

The family reference sheet for the dsPIC 30F line, page 23-7, describes register 23-5 CiTXnDLC. (Page 627 of the PDF linked here.) Bits 8 and 7 are labeled TXRB<1:0>: Reserved Bits, with the note "...
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1answer
208 views

Register behaving like latch in verilog

I have the following block of code - ...
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3answers
151 views

Do registers on a chip wipe when disconnected from the power?

I'm making a project with Arduino, and I have a question about a chip I'm using, the MPU9150, a 9-axis accelerometer+gyroscope+magnetometer. I wanted to know if its registers are wiped when the power ...
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1answer
472 views

PIC24F: problem in AD1PCFG register

Im working ADC in PIC24FJ64GA002 microcontroller using proteus simulation. I've a doubt regards AD port configuration register. I've connected a potentiometer in AN12 pin and channel was selected. The ...
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1answer
92 views

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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2answers
1k views

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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1answer
489 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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1answer
33 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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2answers
157 views

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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2answers
694 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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2answers
610 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
854 views

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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1answer
296 views

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
436 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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2answers
3k 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
419 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
574 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
184 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
937 views

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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2answers
475 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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1answer
2k views

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
629 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
788 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
2k views

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
521 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
4k 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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4answers
34k 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
1k views

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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389 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 ...