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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Assembler program showing ACK even with the wrong slave address, I2C code problem!
I have this project communicating MPR121 capacitive touch sensing keyboard with 8051 microcontroller, with some references I've implemented some I2C code for serial communication between master and ...
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1answer
44 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
101 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 3 is touched, how can i know it?
A set bit means that ...
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1answer
57 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
3k views
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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42 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 read ...
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0answers
52 views
Nested Loops in the ARM instruction assembly language
So in this program I was asked to calculate and print all the armstrong numbers under 10000 just for some background. I can can do this easily in C++ but it has nested loops or uses an array. Can you ...
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1answer
30 views
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
70 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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1answer
22 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
39 views
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
100 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
100 views
How to understand “Power Up Checksum” in embedded system? [on hold]
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
51 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
538 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
78 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
92 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
592 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
317 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 ...
3
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2answers
171 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
60 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
129 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
136 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
80 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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0answers
353 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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0answers
211 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
38 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
152 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
467 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
43 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
216 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
239 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
166 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
39 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
52 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
93 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
99 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
605 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
130 views
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2answers
186 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 ...
2
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1answer
67 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
464 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
332 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
76 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
246 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 ...
5
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1answer
670 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
149 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 ...
