Questions tagged [assembly]

This is a programming language that is at a low level that corresponds with the instruction set of the machine being programmed.

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49 views

How to check the flow of assembler instructions execution?

I'm creating a project that uses I2C serial communication in assembler and I'm having some issues transmitting data and receiving back so I thought I should somehow debug the whole program, besides ...
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2answers
634 views

How to check whether a byte of 8 bits contains 1, assembler 8051?

I need to know how to check whether a byte contains a 1 for touch status in a MPR121 project, so if: 00000010 then pin 2 is touched 00000100 then pin 3 is touched How can I detect it? A ...
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73 views

[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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4answers
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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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989 views

Branch offset out of range ARM assembly

So I tried compiling this code below but keep getting the 1176E error message of Branch offset out of range 0xFFFFFFE8 out of range permitted values are up to 0x00007E on the 5th code line. I ...
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TMOD value for timer 1 in mode 0 in 8051 microcontroller

What will be result of this statement: MOV TMOD,#00H Will it set it to timer 0 in mode 0 or to timer 1 in mode 0? Other statements like: ...
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1answer
588 views

What is the XTAL clock used for in an 8051 microntroller?

I'm trying to design an 8051 microcontroller circuit which uses timers/counters, and the circuit I'm using for inspiration uses a clock generated using the XTAL1 and XTAL2 pins of the IC, shown in the ...
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82 views

Built-in Timer Module HCS12

Why is it preferable to use the built-in timer module rather than using assembly language coding to create delay loops? I've gone through the entire "HCS12 Microcontroller and Embedded Systems" book,...
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1answer
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Can you speed up debugging in Renesas High Performance Embedded Workshop by not flashing after breakpoint

I am debugging an H8S MCU in Renesas High Performance Embedded Workshop 4 with the attached E10A emulator, and find it's very slow when stepping through code because it keeps reflashing the chip ...
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2answers
560 views

Cortex M7 goes to HardFault immediately after reset

I am using the ATSAME70Q21 processor with a Cortex-M7 CPU. My development environment is Atmel Studio 7. I am using the SAME70 XPlained demo board. I am creating some code in assembly language. As ...
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395 views

.dw directive in AVR assembler

the piece of code below is mentioned in 8-bit AVR's instruction set as an example to explain the LPM instruction. ...
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1answer
875 views

What does [WEAK] mean in STM32 startup assembly code?

I was reading the STM32F407 startup file in Keil software to gather some information. I faced this problem: What is the [WEAK] symbol used for? A part of the code ...
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How to produce a middle C on intel 8080?

This is a example problem in my book. Assuming pin 5 of port 4 is connected to an amplifier that drives a loudspeaker, the solution is given as, The frequency of middle C is $$f=261.63\ \text{Hz}$$ ...
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How do we find the bandwidth of a bus?

The data width and cycle rate are used to determine the bandwidth, or the total amount of data that the bus can transmit. An 8-bit bus (1-byte data width) that operates at a cycle rate of 1,000 MHz (1,...
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130 views

What is DIP (dual inline package)? [closed]

I searched on the net, but couldn't understand what DIP is. Is it RAM?
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1answer
6k views

store word assembly instruction in risc-v

I'm really confused about the store instruction in risc-v. When I store word from register to memory, after the word is copied into the mem, does it sign-extended or zero-extended or perhaps something ...
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3k views

How to load immediate negative value in a register?

For example on 8-bit AVR given a register r16 I do something like ldi r16, 44 and this way I can give it positive values from 0 ...
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2answers
2k views

Understanding ARM instruction for numerical literal

I have done an instruction trace while trying to find a bug on a Cortex M3. There is one part of the command I cannot understand. STRB R1, [R3], #+0x01 According ...
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1answer
206 views

ATTiny414 inline assembly operand constraints for IO pin parameter

I'm trying to use the light_ws2812 library to drive WS2812 LEDs from an ATTiny414. The core of that library is an inline assembly snippet that bitbangs the serial line. here it is with the timing-nops ...
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3answers
397 views

Why do we need to declare ports as input/output?

I am writing code in assembly language (AT89s51). When I see a standard program, the ports are typically defined as inputs or outputs. But, without defining them it seems to work fine. How is this ...
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2answers
82 views

How a Computer Represents a Number Electronically

I understand how computers represent decimal numbers using binary. I have yet to absorb this video on how computers add numbers, which looks helpful. Before understanding that though, I would like to ...
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1answer
421 views

AVR-GCC initialization code

Consider the following asm.S .global main main: rjmp main Compile and dump it with these commands: ...
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2answers
83 views

For the first prototype, how many pieces are necessary? Includes 256BGA, SMA, SDRAM

I'll most likely need to re-run. For the first batch of prototype, what is the safest number? Ordered 10pcs of PCBs and ordered 10x components.
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1answer
360 views

Why am I not able to compile this assembly code?

When assembling the code, I get the error : fpu.s(13): error: A1240E: Immediate value cannot be used with this operation ...
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3answers
2k views

AVR assembly language on Division

how do i performs a division by 4 of the 16-bit unsigned value in registers r4:r5 Where r4 is the most significant bit. I understand that by division of 4 which means i have to shift the bit by 2. ...
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1answer
105 views

xorwf literal not affecting z flag even when literal value is same as value in w

According to Instruction Set Description "xorwf myLiteral" should xor contents of "w" with "myLiteral" and if both are same then flag Z in STATUS must be set (not interested where this instruction ...
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1answer
742 views

PIC18F452 interfacing with HD44780 LCD in assembly

I have been trying to get a Hitachi HD44780 LCD to work with my PIC18F452 for a few days now, with no luck. I have tried moving the data lines to different ports on the microchip, I've tried ...
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2answers
654 views

Unsigned 32-bit multiply in AVR assembly

How do I perform a multiplication by 2 of the unsigned 32-bit quantity in registers r18:r19:r20:r21 where r18 is the most ...
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2answers
921 views

24-bit two's complement division in AVR assembly

How do I perform a division by 2 of the 24-bit two's complement value in registers r6:r5:r4. (r6 is the most significant byte.) From what I have this is what I tried: ...
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1answer
78 views

Micro-controller: External Interrupt “ RBIE ”

I'm working on a little project using micro controllers (PIC 16f84A) and got stuck at a point. I have 4 switches and those are the external interrupts now the idea is I don't understand how can I know ...
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2answers
85 views

Loop on flash memory

I have flash memory that I write assembly code on it. I know that flash has limit cycle ( read/ write) If I write a loop that run 100,000,000 times like ...
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1answer
114 views

What is the Microcode in the Intel's Linux Microcode update?

I am a bit confused as to the use of the word microcode in the following links: https://downloadcenter.intel.com/download/27591/Linux-Processor-Microcode-Data-File?product=873 https://newsroom.intel....
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273 views

IT TTT block in assembly language

Why do we have four instructions in IT block for Cortex M4 processor? Is it related to the fact that we have three pipelines for ARM assembly instructions?
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1answer
2k views

Character '0' used but not declared for type std_logic_vector??? (Algorithm state machine)

After adding the counter to my VHDL code am getting the following error: Error (10316): VHDL error at ASM.vhd(31): character ''0'' used but not declared for type "std_logic_vector" Thank you Code: <...
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1answer
195 views

VHDL Algorithm state machine output

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659 views

Where is the location of display buffer on a computer board? [closed]

On an OS development text by Nick Blundel, at chapter 4.1 titled Adapting to Life Without BIOS, it is explained that while graphics hardware is in text-mode, we can write ASCII characters on screen by ...
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1answer
102 views

How close can BGA packages be placed to each other? [closed]

I'm wondering if there is some rule of thumb about how close different BGA packages can be placed to each other. What limits that besides pick and place accuracy? I'll ask a few board assembly ...
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2answers
1k views

Why doesn't my VGA implementation using an AVR microcontroller work?

Problem I'm trying to generate the appropriate signal output for interfacing an AVR ATmega328P microcontroller with an LCD monitor, via the VGA specification. The VGA specification I am trying to ...
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2answers
957 views

Restoring deleted designators on Altium PCB

Is there a way to restore component designators on the PCB without having to delete and re-add the component in the schematic? I deleted quite a few designators while I was laying out the design and ...
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1answer
131 views

Converting negative numbers to hexadecimal number system

I was programming in 8051 and I faced this problem I had to convert the number -10000 to hexadecimal ( 2 bytes) the answer is 0D8h = #HIGH(-10000) 0F0h =LOW (-10000) but how the answer was found /...
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1answer
355 views

How arrays work in assembly language [closed]

I am not able to understand how arrays work in assembly language. In Irvine's book on Assembly Language it's written: *** A string can be divided between multiple lines without having to supply a ...
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1answer
1k views

Effects of no-clean flux or RMA flux residue on signals

I keep on hearing that no-clean solder paste or flux is bad for analog or digital signals because it makes analog signals "noisy" and promotes cross talk on digital signals. Like this claim:...
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217 views

Why accessing the SRAM is slower with AVR XMega load instructions?

The AVR XMega has 16 GPIO registers in I/O space in addition to its internal SRAM. Interestingly the timing of LD instructions differ to these locations: Accessing the (rather large) I/O space is ...
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1answer
112 views

Where can I learn assembly? [closed]

I am a student and didn’t find any proper video even on YouTube for this. So, Where can I learn Assembly Language Programming for the 8085 Microprocessor? It would be very helpful if someone would ...
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1answer
176 views

8085 Programming Basics

Bcz of CALL, SP will be decremented by 2. Then bcz of POP, SP will get incremented by 2. So, SP will be 27FFH. But, I am confused with HL register part. Please help me with the above problem.
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4k views

Why does __libc_init_array cause an exception?

After a long time trying to debug why my simple blinky code for my STM32F446RE microcontroller was not working i discovered a line in the bootup assembly file that i was linking to it which was ...
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2answers
557 views

How is this kind of soldering done?

The solder fillets around the base of the header pins are almost flat - very different from the kind of fillets you'd expect to around a 0.1" header. These kind of fillets are very common on ST's ...
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1answer
179 views

instruction in 8051 assembly

I have problems understanding what does this instruction do MOV number,#(4+3)SHL(4)SHR(4) googling gave me this "operand1 SHL operand2" which is different than the instruction i wrote above . Can ...
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1answer
110 views

ASM Chart for synchronous system

I have an ASM chart design problem that I've been stuck on for ages: A lift in a building only has a maximum capacity of 2 people. Two sensors detect people entering (input ENTER) and exiting (input ...
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1answer
548 views

Why does out command works wrong? (Proteus 8086)

I am trying to create an output unit for 8086 microprocessor which is connected to MP's 00ABh(10101011) address. I used 74LS373 for that. This is how I made connections: When I run the code below, ...

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