Questions tagged [8051]
The "8051" is a (still) very popular chip in the Intel MCS-51 micro controller series.
251
questions
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3answers
82 views
4-bit mode of LCD-1602 using 8052 µc
I try writing "NO" in the LCD using 4-bit mode. So, I programmed the AT89S52 to send the upper nibble first to the last 4 data inputs of the LCD. I used AND operation to eliminate the lower ...
0
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3answers
63 views
Finding maximum sink and source currents from datasheet
How can I find the maximum sinking and sourcing currents of different pins in a microcontroller (namely 8051) from its datasheet?
Edit: I have downloaded and looked at the datasheet, I just can't read ...
0
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2answers
39 views
How does the OV(Overflow flag) of the 8051 work and how does it differentiate between signed and unsigned digits?
If a number is 8 bit, the maximum value it can have is 2^8 or (1111 1111).
In the OV flag, the last digit or the MSB decides the sign, but how does the overflow flag know if it is the "signed MSB&...
0
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1answer
38 views
What is the difference between Register Addressing mode and Direct Addressing mode(8051)?
I find that there is no difference between the Register Addressing mode and the Direct Addressing mode.
Can anyone tell the difference with respect to the 8051 microcontroller ?
1
vote
1answer
56 views
8051 / EFM8LB1 / programming via C2 after PCON0.STOP := 1?
Yesterday I wanted to see, how much power my EFM8LB1 uses, when it has just this firmware with bootloader disabled:
...
0
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0answers
31 views
Understanding oscillation frequency for SAF-C509 processor
Good day.
For the time being, I'm reversing automotive ECU which has Intel51 architecture processor - SAF-C509 by Infineon/Simens. Its command exection part has 6 states with 2 phases for each state. ...
0
votes
1answer
99 views
Encryption library for an 8051 microcontroller
I've programmed an 8051 microcontroller to send data out through an external transmitter (just a few bytes per transmission). I'm looking to encrypt this data in my microcontroller's program.
I have a ...
0
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0answers
38 views
0
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1answer
61 views
Need more than two external interrupts in 8051
I am working with 8 YS-17 flame sensors and may need more in the future. There are only two INT0 and INT1 in port 3. Is there any way to get the other interrupts or I/Os to work as external ...
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votes
1answer
56 views
Is anyone familiar with EDsim? [closed]
I'm learning the basics of the microcontroller 8051 and I wrote a program that requires me to toggle a button situated in the ADC of the chip .
Since I don't have the board , I worked on a software ...
1
vote
2answers
238 views
firmware testing methods
This is my first question here from the community :)
So I have inherited some bad embedded code, the whole firmware is a messy spaghetti state-machine that has an infinite number of states! and it is ...
1
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1answer
48 views
How to use mode 0 in 8051?
I tried to use timer0 in mode 0 of AT89S52 for blinking a led for 1 second using this code:
...
0
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1answer
92 views
.c to .hex file conversion without using any IDE
I am new to microcontroller programming.
I have a program written in C or assembly language which I need to convert into a .HEX file to flash into the 8051 microcontroller. I do not want to use an IDE ...
0
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1answer
76 views
8051 initializing data in external memory
I am trying to understand the use of external memory with an 8051. When you are using external memory with something like C8051F962 where you have to configure the ports to access the memory, how do ...
0
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3answers
101 views
Why 8051 microcontroller uses four different ports for I/O instead of using address bus and control signals
8051 has four ports for I/O .Therefore four peripherals can be connected to it at a time .
My question is why doesn't it use the address bus to activate a specific peripheral ...and then use the data ...
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votes
1answer
134 views
Cloning a 8051 flash with an Arduino
I have a 8051 microcontroller and want to copy the flash memory.
I have an Arduino, a cp2102 usb to UART module and an 8051 microcontroller. The 8051 is a zen3309AD.
How do I achieve this task. I ...
0
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1answer
42 views
What is the difference between ram and registers in 8051 vs arm v7?
Recently i am confused between the difference between ram and cpu registers.I have studied 8051 arch. and in that we had addressing for cpu registers in ram level (e.g. the adddress for R0 register in ...
1
vote
1answer
200 views
8051 to I2C backpack/4 bit LCD Byte Construct Probelms
Been feverishly writing bit bang code in assembly for this I2C backpack/4 bit LCD and dont quite understand the binary constructs I need to display text. Im trying to learn this the real way, not the ...
1
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1answer
88 views
What is a page in 8051 microprocessor?
https://www.hobbyprojects.com/8051_tutorial/acall_absolute_call.html
I was learning about acall on the above website, but then came across the term page. What exactly is a page?
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1answer
977 views
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1answer
76 views
How these timer values are derived?
I have a 8051 micro controller ,it has timer0,1,2,3 with different modes.
in timer0,mode0, i got a sample code (as shown below).
datasheet 8051
from that code
...
1
vote
1answer
90 views
In asynchronous communication how is the frequency same but clocks of both devices different?
Am currently studying 8051 microcontroller and in the course the lecturer told that in communication the frequencies of sender and receiver should be same else they will get different bits of data at ...
1
vote
1answer
287 views
What happens at hardware level when we feed a code? [duplicate]
I wanted to know what hardware is installed in 8051 such that whenever i write a program it accepts it and execute it.
My query is what happens at the hardware level whenever i feed a program to 8051.
0
votes
1answer
103 views
Two switches and two LEDs using 8051
I am trying to work around a circuit and my requirement is as follows: -
There are two inputs and two outputs. Each input controls an individual led. I am writing a code for this requirement using a ...
-1
votes
1answer
47 views
minimizing waiting time for 8051 port state
I made myself a project with standard 8051 microcontrollers (AT89S52 and AT89C4051) and will be making more with the same due to price and availability.
When data is being sent from one GPIO pin from ...
1
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0answers
49 views
ENC28j60 ethernet interfacing with efm8lb1 help needed
I am a newbie to ethernet controller. I went through ENC28j60 documentation But I couldn't find a proper example similar to my project.
EFM8LB1 will read some sensor data (for example sensor data '...
1
vote
2answers
231 views
How can I code in a buzzer while using a 7-segment in an 8051
I'm currently working on a small queuing system where whenever someone presses a button (which I have linked to INT0), my 8051 would increase the register and would display a higher number on the dual ...
1
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1answer
94 views
Why does this driver not have a load resistor?
Im trying to drive a motor with this kind of circuit since my micro is an old 8051. The voltage I use is 5V and PowerV is also 5V.
I also have a 56 ohm 1/2 watt resistor in series with my motor ...
0
votes
1answer
47 views
Weird error pattern on CC2541, the 8051 core
I am playing with the debug interface on the TI CC2541. It seems to be working fine, seeing correct chip ID etc.
The interface has a DEBUG_INSTR command that lets you submit and execute an ...
0
votes
1answer
118 views
Grounding GPIO pins during 8051 programming
I'm trying to make a programmer for the 8051 microcontroller IC's, specifically the AT89C2051. I saw a circuit online (the blowit programmer) in which the unused GPIO pins are left floating.
When the ...
0
votes
1answer
95 views
interrupt-on-change on 8051 microcontroller
I am trying to read the speed or number of rotations pulses of a self-made encoder motor.
I am using an AT89C52 microcontroller. It gives external interrupt on rising or falling edge.
How can I ...
0
votes
1answer
75 views
Chaging EA/VPP by software on Intel MCS-51/8051
I'm designing a circuit that uses the combined Program/Data bus from Intel MSC-51 as advantage.
By the MCS-51 specification it has an internal 4K ROM and a EA/VPP pin that if set to high will access ...
0
votes
1answer
498 views
Converting “MPR121 capacitive keyboard” sensor filter data into capacitance values?
The project that I'm working on, the MPR121 capacitive touch sensing keyboard connected with a 8051 microcontroller, my first intention when I started implementing the project was to measure the ...
3
votes
2answers
2k views
8 channel quiz buzzer circuit using 8051 microcontroller
Project: 8 channel quiz buzzer circuit using 8051 microcontroller from this site.
For the first candidate who presses their button, their number will show on the 7-segment display and the buzzer will ...
0
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0answers
71 views
ACK even for the not existing register, I2C problem!
I'm implementing this project with MPR121 keyboard communicating with 8051 via I2C before I get further into the program I wanted to know whether the sensor is communicating with the board, giving the ...
0
votes
1answer
126 views
8051 Open Drain Operation
While studying I ended up finding this question.
Write the value (in hex) of the P1 after the execution of the code below.
...
0
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1answer
192 views
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 ...
1
vote
1answer
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 ...
0
votes
0answers
54 views
Check if the slave is receiving data from microcontroller and transmitting back successfully, I2C?
I have this project where I have to communicate MPR121 touch sensor keyboard with 8051 microcontroller via I2C, I've implemented the code and when I execute it I don't really know whether slave is ...
1
vote
2answers
600 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 ...
0
votes
2answers
967 views
8051 microcontroller problem to find execution time of part1 for a given code
For the below mentioned 8051 assembly code:
Time elapse: MOV R0,#100
Part 1 \$ \quad \, \, \,\,\$ : MOV R1,#50
Part 2 \$ \quad \, \, \,\,\$ : MOV R2,#248
Part 3 \$ \quad \, \, \,\,...
0
votes
1answer
739 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:
...
1
vote
3answers
962 views
555 Clock Circuit - how to choose resistor value? [closed]
I need to design a 555 clock circuit to output a clock pulse of a specific frequency. The circuit I'm using is this one (from here):
I've used this circuit before and it works fine but the website ...
0
votes
1answer
541 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 ...
0
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1answer
290 views
Reset MCU with a 1-0 button
I am working on a silabs C8051 MCU. It has a sleep mode which should be woken up by a reset. The mcu should start working (wake up from sleep) when the button in connected to Ground (Otherwise it is ...
2
votes
1answer
143 views
old 80C31 circuit not working. EPROM data retention issue?
I have an old piece of pro-audio gear in for repair. It dates from 1990. It was a fairly high-end piece of gear at the time and still has some value so it is worth repairing. But the symptoms I see ...
0
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0answers
44 views
CC2530: adapting AVR/pgmspace.h for Zigbee
Goal: Adapt ENC28J60 codes written for ATMega328p (http://tuxgraphics.org/electronics/201204/embedded-ethernet-client.shtml) for CC2530.
Problem: No equivalent library for AVR/pgmspace.h available ...
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0answers
73 views
minimalist serial port addon to a basic 8052
Currently I have two microcontrollers connected to each other so that I have two serial ports. One to the PC and one to a wireless radio module.
Now I'm considering replacing one microcontroller with ...
0
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1answer
47 views
Bidirectional data bus divided into nibbles not returning correct data - 8051
Since I have 10 I/O lines connected between two microcontrollers (AT89C4051 + AT89S52), I am trying to get away with elegant data transfer. Instead of spending months redoing an entire circuit board, ...
1
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1answer
51 views
Byte-Banging 2 8051's using port addresses
Currently I have two microcontrollers setup in which entire ports are connected to each other (P1.1 connected to P1.1, P1.2 connected to P1.2, etc). I also have two pairs of extra GPIO pins connected ...
