Questions tagged [bit-bang]

A software implementation of a digital data stream on a digital I/O line. Bit-banging is opposite to using specialized hardware such as UART, MSSP (in PICs), USCI (in MSP430).

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44 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 ...
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1answer
121 views

When should I change a logic level and how long should I hold it?

I'll start out by saying I'm a total newbie to this stuff, so I apologize if this is a silly question. For context, I'm trying to bit-bang the Low Pin Count bus using a FT232H. Here's a timing ...
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1answer
275 views

Simpler code than bit banging to get multiple serial hardware working with 8051

I created a circuit like the following: I have sub-circuits that all take serial data as input and do miscellaneous processing with it. Most of the sub-circuits are just light displays. I want to ...
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2answers
347 views

One master to 32 slave pic microcontroller communication, bitbang

I'm trying to communicate with 32 microcontrollers (PIC 12f675). These are used to control 32 DC motors and 2 sensor for each PIC. So only two pins are left to communicate with master device. I want ...
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1answer
2k views

STM32: Manchester coding bit banging implementation problem

I want to use Manchester Coding for my DALI Master-slave project. I am using two boards for this project, one is STM32E407 and the other is STM32F3Discovery. As an initial step, I want to test for ...
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0answers
204 views

Half-duplex Bit-Banged Port for 8051 microcontrollers too slow?

I was looking at: https://www.maximintegrated.com/en/app-notes/index.mvp/id/3524 and it claims that one can achieve over 2mbps on a 32Mhz clock when bit-banging with an 8051. That means 1mbps on 16Mhz....
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144 views

pic bitbang SPI library with variable frame lenght

Im trying to send an SPI frame that is 12 bits long using a pic 16F1455. Im afraid i cant do this using the hardware SPI module , which has a fixed lenght of 8 bits. I think i can do this with ...
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2answers
349 views

Does clock speed matter when recovering from I2C bus lock up?

When there is I2C lock caused by slave device driving the SDA line low you need to manually generate a few clock signals by doing a simple bit banging on the SCL pin. I thought that this need to be ...
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2answers
292 views

When do you release and re-aquire control over SDA around an i2c Ack?

I am having odd behavior with Energia's Wire library, so I figured that I would attempt to do i2c myself. I'm writing my own (bit-bang) implementation if i2c and keeping it pretty simple. For now, I ...
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1answer
424 views

SDIO bit banging

I need to interface a wifi chip to my ARM 9 board, it does not have in built SDIO so i am thinking to interface via bit banging. Questions: Is it possible to interface SDIO via bit banging If not ...
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1answer
561 views

STM32 handmade USART driver

I designed a new electronic card which has a STM32F4 microcontroller on it. Each peripheral except the Wifi module works. Wifi module is supposed to communicate with the controller via USART channel ...
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144 views

Can I use GPIOs to bit-bang in SENT protocol

I want to use a STM8 controller for a project(as I am familiar with micro).This controller gets the data from sensor and process it and sends data to another ...
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2answers
214 views

Prevent bit-bang data-in line from back powering device?

I'm building a Z80 machine from components, to talk initially to a PC via bit banged I/O through an FTDI USB cable, and I've little idea how best to avoid back powering the Z80 board from a 5V data in-...
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598 views

Is it a problem with SPI bit-banging or the mode

After hours of debugging the SPI send bit-banging function and probing, I have come to a point where I could no longer understand whats causing the Si4455-RFIC to always return response of 0x00, ...
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1answer
461 views

Significance of bias when driving an LCD

I've got hold of several bare-glass T218010 LCDs and would like to drive them with a bare MCU (or, rather, an MCU plus a couple latched-output SIPO shift registers such as 74HC595). However, the only ...
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1answer
144 views

UART works when I open minicom before starting UART

I am trying to send out large amounts of data at 115200 via UART. I have come across a rather strange problem. I am sending out data in the while loop of the MCU. The MCU is not doing anything else. I ...
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2answers
119 views

16 separate lines via USB

So let me start apologizing if the question doesn't make any sense at all, I'm a total noob and I haven't quite grasped most of the concepts yet. I have designed this small visual indicator, which ...
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1answer
641 views

Verilog outputting specific bit from register to output; getting constant 1's

I am trying to create an program that bit bangs a value from an FPGA to an arduino. In the module I created, every other clock cycle, the FPGAdata output should be set to the next bit of t. The ...
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3answers
1k views

I2C: Unable to Read Multiple Byte using Bit-Banging method

I am using Bit-Banging for I2C communication via PIC24FJ128GA010. The code works fine for writing 16bytes to EEPROM ( I recieved ACK = 0 for every Byte write ). While reading EEPROM I am able to ...
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3answers
2k views

Is the SPI Interface just a protocol or actual hardware?

I want to use the SPI interface between a PIC and an ENC28J60. However, there are no pins on the PIC called MISO or MOSI that I can use for SPI. So is SPI just a protocol, which I can use with any ...
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2answers
855 views

ATtiny2313 vs ATtiny84 software compatibility

I make and sell a variant of the USBtiny AVR programmer. It uses an ATtiny2313 clocked at 12 MHz and does bit-banged USB using hand-tuned assembly language (that someone else wrote - it's an open ...
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3answers
413 views

Approach to 8 channel bit banging

I'm looking at controlling some WS2812 5050 RGB LED strips from a microcontroller. I've successfully played with the Adafruit Neopixel library and I've written some code on a PIC18F2455 which I've ...
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1answer
176 views

Getting 5V Output on FT245RL

I've got Sparkfun's FT245RL Usb to Fifo Breakout Board. I need 5V output from data bit ports(D0-D7). While I'm working with it, I've found out I need to unsolder SJ1 jumper between Vcc and Vccio then ...
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0answers
805 views

Asynchronous Bitbang mode vs Synchronous Bitbang mode

I am still newbie in the field of electronic, and I have to write program to flash LED light as well as receive light data via photodiode. I am currently using FT2232H mini module. I have trouble ...
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1answer
354 views

Bit-banging I2C question

When bit-banging I2C using 2 PIO lines do these lines still need to be pulled high? Obviously using a dedicated I2C bus the lines must be pulled high as the pins are open-drain outputs but PIO pins ...
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1answer
945 views

bitbanging i2c problem with ACK from slave

I am trying to implement bit-banging i2c to communicate between an atmega128A's GPIO and an SHT21 (I2C bus was used for some other devices). The first task is to send a write sequence to the SHT21. ...
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3answers
2k views

How fast can ARM Cortex M0s/M3s bit bang?

I have not yet used ARM Cortex uCs, only AVRs Firstly, how fast can they: Stream 1024+ bits (serially, from bytes in RAM) out of a pin, with no pauses/jitter Stream 1024+ bytes (parallel, from RAM) ...
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3answers
16k views

Max switching frequency of GPIO pins of modern cheap FPGA

How can we estimate maximum switching frequency of GPIO FPGA pins? What is maximum data rate achievable when connecting two FPGAs together without using of integrated high-speed transceivers? Or when ...
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1answer
729 views

Parallel NOR Flash ROM in-system programming issue (Micron M29F160)

I'm attempting to program a Micron M29F160 Flash ROM (datasheet) that is memory-mapped into a larger system, and I want to program it from the external interface of that system, but I can't seem to ...
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2answers
663 views

Bit-banging a ShifBrite led driver with a PIC

I am having problems making communicate a Shiftbrite A6281 led driver with a PIC18F4550. What I am trying to do is to send the RGB values to the driver in order to select the color of the led, but I ...
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3answers
452 views

Terminology question: does the term “bit-banging” implies not using external signal edge interrupts for timing?

Assuming I realize some communication protocol (e.g. SPI or I2C) just with GPIOs (no dedicated HW). In order to handle timing, I can either: set interrupt on the CLK edge set timer interrupt and test ...
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1answer
279 views

Bit-bang TX problem

I need some help. I had to create a new serial for my motherboard. I decided to emulate a serial via bit bang. The code is below. I am finding problem in my code sync bit bang with a traditional RS232 ...
5
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1answer
8k views

How to write to 93LC46B EEPROM from an Arduino using SPI

I have a question regarding eeproms and an Arduino (I am using Arduino Uno). I have the following eeprom: 93LC46B. From the datasheet I understand that in order to write the integers ...
6
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3answers
435 views

i2c external pullup kills communication

I am using an MCP23017 (which shouldn't matter tho) to extend the number of GPIO pins of an arm based linux computer using i2c-dev bitbanging. It all works fine with wires of a few centimetres. The ...
4
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1answer
2k views

FTDI-based programmer works with ATmega but not ATtiny?

I'm using an FTDI-based bit-bang programmer for my AVR MCUs with AVRDUDE. It works perfectly with ATmega32A, but does not work with ATtiny45. The command that I use to try if it works is: ...
3
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2answers
1k views

SPI flash memory doesn't work without huge delays

For my graduation work I am developing a microcontroller system where the MCU (MSP430FR5739) talks to an SPI flash (SST25VF080B to be particular). I've achieved this without using the eUSCI SPI master ...
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5answers
5k views

Arduino software serial - full duplex

I need two serial ports for this Atmega328 Arduino project, but this processor has only one hardware UART. The processor, hardware design, and programming environment are already set, and I cannot ...