Questions tagged [register]

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

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Has anyone configured/initialized a BCM89501 to use BroadRReach mode on all 4 channels?

I have a board where my configuration seems to get the individual channels in a good state about 80% of the time, but that means that I frequently have one or more bad channels on a board. Which ...
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NVIC memory map ARM cortex M3 STM32f103

I do not understand the following memory map regarding the NVIC registers in Programming Manual for STM32f103 page 129. It says that the offset address for NVIC_IPR0 is 0x300 and that of NVIC_IPR20 is ...
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How can I transform the code for a read-write register to a read only register in Verilog?

I have the code for read write register here ...
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Multiplexer handling 16 bits

Design the VHDL components (Register, Decoder, and two Multiplexer 16 bit) and interconnect them to build a register file. The schematic shows only four registers. Your solution should implement ...
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How to specify a value for each bit of the reg in Verilog?

I want to declare a reg of 8 bits and set the value for each one of the bits separately (based on another "counter" reg) inside ...
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Verilog Reg File: Cant mix blocking and non-blocking assigment

I want to implement a blocking read to read the data as soon as it is written. I am trying to implement a MIPS 1 pipeline and i need the data to be available in the same clock it is written. The flips ...
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Phase register in phase accumulator

In the following flow diagram: Is the "phase register" a one-bit register? What does it basically do with that summation mark? What type of register is it? I basically do not know what the phase ...
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Writing to registers on I2C device

I'm currently working on a side project which uses an SSD1306 128x64 OLED display. I'm then using I2C to communicate to this. However, I'd like to better understand what exactly is going on when I'm ...
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Dinamically change PWM frequency with interrupt with STM32

i'm using an stm32f4 to control a stepper motor. I'm not sure if i need PWM mode or OC Mode or OnePulse Mode. I can generate a fixed frequency PWM wave but since i need a particular acceleration/...
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Assembly language, accessing bytes of memory

I have some memory address 0x00000100 that I want to read from. The lower 4 bits read from this address indicates the states of 4 buttons - So bit 0 shows the state of button 0, bit 1 shows the state ...
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Why do we need 'R_out' in 2-BUS arch?

Given some abstract architecture of CPU: Note that this CPU has 2-BUS. Why do we need the R_out and R_in? If I use Gra/Grb/Grc then obviousely I will need R_out. The Same for R_in when I use Sra/Srb/...
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variable should not be used in output port connection

I searched random verilog heirarchy to understand how to properly instantiate modules. I found one on https://www.altera.com/support/support-resources/design-examples/design-software/verilog/ver_hier....
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Processing ADC conversion result: DMA vs Processor Registers

I have a periodic ADC conversion (every 50 micro-seconds) and I use the result to do some further calculations and update the PWM load registers. The ADC is triggered by the up-down counter of ...
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Build A Two Port Write and Two Port Read Register File with 4 Registers

I am facing problem in my current task. I need to build a 2-port write and 2-port read register file with 4 registers. I am able to do the 2-port read part but I could not do the 2-port write part. ...
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STM32f103 interfacing with adxl345 via i2c

I am working on interfacing ADXL345 accelerometer with STM32F103 blue pill board through I2C communication. I have written the code in Keil software by surfing the internet which works fine sometimes, ...
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Can I use a photodiode as a switch for a shift register?

Let's say I have a photodiode, a shift register (74HC595) and a 5V source, and I connect these as: 5V source -- photodiode -- shift register data input. (And other voltages to feed the register ...
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Home brew CPU register trouble shooting

update Apparently I’m an idiot. It took me this long (hours) to check the supply voltage of the flip flops, which was at .25 volts from a bad connection. Rookie mistake. Hard lesson learnt. In the ...
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How to produce a register bank comprising four such registers in Logisim, sharing common data lines D0 … D7 and outputs <Q0 … Q7>?

I made a D-Latch circuit that looks like this: and I converted it into a subcircuit and made an 8 bit register like this: But how do I make a register bank using four such registers? Any help is ...
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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?
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How to modify BRR and BRSS registers to stm32f4 from stm32f103

I'm trying to modify stm32f103 2x16 lcd library to stm32f4. There are BRR and BSRR register on stm32f103 but there aren't similar register in GPIO_TypeDef structure on stm32f4 so i don't know how to ...
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Renaming a special register

I noticed that RISC-V, like some other RISC architectures, by convention treats register 1 specially, using it as the link register, holding the return address for function calls. If most code ...
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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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Register readback for ADC WM8253

I am trying to read the contents of register written in serial mode of WM8253 using SPI in Basys 3 FPGA. Link to Datasheet. I'm reading from register '011100' but the result that is read is always "...
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[Updated]How to select the values to move in assembler?

I'm trying to make the led blinks on the tm4c1294ncpdt, so the basic idea its to make 2 routines , one to select the GPIO port (in this case the F) and other to keep up on and off. the setup routine ...
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MAX17205 DevName reading wrong, but other default value is correct. Why?

I am using the battery fuel guage MAX17205 through I2C bus. The Device Name register that I read from it seems have a different value than what the datasheet states: I am reading a 0x2a7c, but it'...
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What stops an assembly program from crashing the operating system? [closed]

First of all, I am a beginner, so if this question sounds silly, please point out the incorrect assumptions. From what I understand, the job of an operating system is to manage hardware and the ...
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74hc595 sinking, not sourcing

I'm trying to get a sn74hc595n working with an arduino Due, eventually I will be hooking up each output to an NPN to drive Nixie tubes (I am switching my design from a due to using a esp8266 so I need ...
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When to monitor UxSTAbits.TRMT and UxSTAbits.UTXBF

According to the reference manual on UART for PIC here(page 7), the UxSTA register have two read-only bits; TRMT and UTXBF. While writing a simple transmission program over UART, I didn't notice any ...
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Clk pulses needed to retrieve data in registers

I know that to store n bits of data in a SISO register , n clk pulses are needed . And to retrieve the data only n-1 clk pulses are needed because 1 bit is already available at the output . In a SIPO ...
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What prevents the construction of a CPU with all necessary memory represented in registers? [duplicate]

Modern CPUs employ a hierarchy of memory technologies. Registers, built into the chip have the lowest access times, but are expensive and volatile. Cache is a middle-man between RAM and registers to ...
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Where the appropriate word size is selected for the operand?

This question is about a 32 bit Intel Chip using x86 assembly. My question specifically is what happens when you do the mov reg, mem instruction where the memory operand is a word (16 bits) from DRAM. ...
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Initial register value in synthesized design is always 0

I'm using Altera Cyclone IV EP4CE6 as my FPGA. Compiling the design in Quartus Prime 18.0.0 Lite Edition. The State register in the below module appears to be 0 ...
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STM32F4xx, How to use RTC correctly?

I'm trying to run RTC, but there are two problems. 1) It is impossible to write the security key in the WPR register. 2) It is impossible to set the time and date in the TR and DR registers. I tried ...
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PISO shift register with first input

I have on my board two PISO shift registers in series, giving an output train of 16 bits. The problem is that the order of the bits is reversed compared to what I need. That means, the last input of ...
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SPI problem with STM32F103

I am trying to connect blue pill board(master) to arduino nano(slave) over SPI and read what I have sent on serial monitor. However I haven't been able to get SPI working. I run a timer to generate an ...
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What's the difference between a hardware register and a shift register?

There are two different wikipedia articles but they don't articulate the difference very clearly. Is the main difference that the shift registry uses a clock?
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HDL code convention for register resets

When it comes to (synchronously) resetting registers in HDL (I'll use Verilog), is it considered bad practice to code the reset combinatorially? As far as I can tell, the following two snippets are ...
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Which register holds the final arithmetic and logic results?

This Wikipedia page says an accumulator is a register in which intermediate arithmetic and logic results are stored. So which register holds the final result?
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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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what does “ports can be registered” mean? For circuit design

I have a homework. I must design a circuit that makes addition with signed and unsigned numbers. I will use registers. I need two output ports. It says "8-bit output ports (2 ports: one for unsigned ...
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Clock domain cross and metastablilty problem

I understand the problem of metastability and understand that we can't get a stable value in a bounded time so we need unbonded time but it is not practical, so we put another flip flop with no ...
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Finite State Machine FSM

I understand how to make state diagram and make combinational logic (gates) to get a boolean equation for the next state bits and the output bit, but what is the function of ROM here ?
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When does a register need to get a load control-signal in order to be updated at the next clock? [closed]

I know this is a pretty basic question, but I didn't succeed to find an unambiguous answer. Does a register need to get load signal in the cycle in which the new value computation is made? or at the ...
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What is the tradeoff between number of register files and logical register specified in the ISA?

As the limited number of logical registers are opened to the user and compiler, it incurs the false dependency problems such as WAW and WAR. Therefore, to solve this problem, lots of ...
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Error (suppressible): (vsim-3601) Iteration limit Quartus

I have created a Simulation of a 4 bit register in quartus. Each of the four D flip flops test fine by themselves, but when I test 4 of them connected together into a register, I get the "Error (...
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What is this array-like notation of registers in datasheets?

I am reading BMP280 datasheet (pressure&temperature sensor). On different pages they use the following notation: $$register\text{_}name[a:b]$$ where a, b are integers. For example, on page 13 "...
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Are memory-mapped registers actually implemented as real registers?

I am currently trying to better understand microcontroller-architectures and I am particularly studying the ARM cortex-m3 right now. What I have always wondered is, if memory mapped registers are ...
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Verilog register output: reg or wire?

If I want to model a simple register I would expect to have an internal 'reg' element to hold the value and I would connect this with a 'wire' output. The reg drives an internal output. However, I'...
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Pull up/down a pin on a PCA9536 does not register?

Quite a obscure question here, concerning a very specific I2C expander IC, however I believe that this example can be replicated with most expander bus ICs. I am using a PCA9536 to switch the 4 pins ...
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Q: Digital potentiometer MCP4162

I am having a hard time understanding the MCP4162 Datasheet. The application for the digi pot is have an Ardunio to control the wiper resistance so I can have a constant desired output voltage ...