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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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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
73 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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1answer
71 views

How to understand “Power Up Checksum” in embedded system?

For an Embedded hardware system, how do we understand the "Power Up Checksum" in the initialization part? How does it work in detail? (Where does it check, what is the mechanism) A "Power Up ...
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1answer
38 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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34 views

Low Level Interface/Primitives that Interface with RAM (DDR4)

I am trying to understand how CPU Assembly Instructions interface with the RAM? And how RAM works out those instructions. So for example when CPU says: ...
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1answer
481 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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1answer
1k views

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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2answers
61 views

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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2answers
90 views

DIP (dual inline package) [closed]

searching on the net, but couldnt understand for what is used DIP? Is it RAM? Will be glad for your answers.
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1answer
184 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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2answers
200 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
135 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
46 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
106 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
68 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
90 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
79 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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29 views

External assembler function for digital signal processor

I need to create external function on TMS320C5515 Fixed-Point Digital Signal Processor around BFXTR command. I need to write some value directly into memory. I ...
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281 views

Servo motor interfacing with 8051 by assembly language

I know the principles of servo motor and programming it, I already done it with FPGA and adjusted the PWM like I wanted. But with 8051 assembly, I can't do the PWM or generate the 20 ms for the motors....
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155 views

Accomplishing division and remainder with AVR Assembly

Given an unsigned 8-bit value in r19 I want to figure out what the remainder is after division with some immediate value x. The ...
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0answers
37 views

MPLAB strange code jumps

I am writing assembly code for the 16F84A microcontroller and have run into some issues. I've implemented a 1 second time delay code which repeats itself consecutively for a total of 3 seconds, ...
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1answer
131 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
322 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
41 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
157 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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1answer
188 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
146 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
37 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
51 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
85 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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3answers
95 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
464 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
125 views
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2answers
152 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
63 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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1answer
370 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
269 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
65 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
233 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
552 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: Flux ...
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0answers
130 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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48 views

Port 1.0 keeps going HIGH when I move a number to Port 1 (8051)

So I'm trying to move a hex number to Port 1, for example 2H on Port 1 should give: 00000010 but my problem is whatever number I move to Port 1(except 0H) sets Port1.0 to HIGH, I don't understand why ...
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1answer
146 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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1answer
1k 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
232 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
128 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
61 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
242 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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1answer
67 views

assembly timer code [ C8051F340 ] explanation [closed]

Hi my problem is that I cant understand this code when I test it on my microcontroller Si Lab [ C8051F340 ]and let it run step by step My problem is basically is when I test the program on my ...
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1answer
108 views

How exactly do clock speeds of computers relate to operation speeds?

I was wondering about this the other day when I was explaining binary and hexadecimal to a friend of mine and this came up. The question goes something like this: How exactly do instruction ...