Questions tagged [bit-bang]

For questions pertaining to bit banging, a serial communication technique.

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Edit the UART communication protocol

Is it possible to manipulate the bytes on a bit level prior to sending through the hardware UART, or do I have to implement a software version (bit-banging)? I was thinking of changing the clock ...
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0answers
25 views

Varying possibly broken behavior of different GPIO pins on bitbanging LED display driver

I connect Raspberry Pi 3 b+ directly to 8x8 LED display, packaged with max7219cng display driver. To control GPIO pins, I'm using baremetal code, written by myself. For working with GPIO I've ...
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1answer
67 views

PIGPIO bit banging UART - SLR to plaintext

I've managed to read UART input by SLRO and SLR commands from pgpiod, however, SLR returns UART bit-banged data in the following format: [number of read bytes] [bytes] http://abyz.me.uk/rpi/pigpio/...
3
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2answers
141 views

Random i2c SDA spikes (bit flip)

I'm trying to communicate with an old i2c device and I'm getting wrong read values, and possibly even some incorrect write values too. My logic analyzer shows random highs in the middle of a low. ...
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0answers
226 views

pigpio python serial wave output not correct

I am trying to use joan's pigpio to write a serial command on my Rpi 3 gpio 14(UART0TX).My goal is to write a command from the pi to another device. When i send the command i do not see the ...
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0answers
23 views

Writing to a sensor register using i2c bitbanging library not working - PiGPIO library on Raspberry Pi

I am trying to configure a sensor connected to Rpi over an i2c bus. I am using PiGPIO library with Python to do this. To configure the sensor, I need to write a certain value to some registers and ...
4
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3answers
3k views

Multiplexing 4-digit 7-segment display is flickering

I connected a 4-digit 7-segment display to the GPIO-port. It uses 8 ports for the LEDs and 4 ports for multiplexing via PNP-transistors. It is running so far with a loop written in C program: while(1)...
0
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1answer
247 views

pigpio library serial_wave confusion

I am trying to use joan's pigpio for python to try to write a command from a rpi3 GPIO pin to a peripheral device. the peripheral device uses UART and when it receives a data packet it will then ...
6
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1answer
624 views

I2C repeated start with BitBanging not working - Pigpio library on Raspberry Pi B+

First post here on the forum! Been getting a lot of help here from all the past posts and I am grateful for such a great community. I have been trying to use Repeated Start by using the PIGPIO ...
3
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1answer
2k views

Bit-banging with Python

I want to get and change the I²C address of MCP4728 chip. To do this, one has to coordinate I²C communication with another LDAC pin register. After posting the question here, Reading and writing ...
0
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1answer
625 views

How many i2c buses?

My project involves talking to 16 IMU's at once. I can do 2 MPU6050 on one bus because of addressing, but I pretty much need 400kbps for throughput. I was looking over the pigpio library to see if I ...
7
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1answer
469 views

Bit waveform clarification

I have been trying to learn more about bit transmission through the uart, and I have the following code in python to transmit information: import serial ser = serial.Serial( port='/dev/ttyAMA0',...
1
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1answer
566 views

High speed bit bang GPIO reading

I'm trying to establish a UART communication link by means of bit-banging. For the TX part, I am using the pigpio lib to form a 1Mbaud wave of bits (gpioWaveAddSerial). I have checked it and it with ...
2
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2answers
987 views

How to read RHT03 sensor

I have this sensor: http://cdn.sparkfun.com/datasheets/Sensors/Weather/RHT03.pdf On page 3 there is an image showing how to communicate. I also attach an image of this here: In my understanding, ...
29
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3answers
15k views

Can Raspberry Pi reliably bit bang a 9600 baud serial and is there example code?

I am wondering how feasible it is to use bitbanging to drive a 9600 baud serial via the GPIO pins on the Raspberry Pi. Obviously, Linux is not a terribly good platform for bitbanging, as there is a ...
3
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4answers
1k views

Inconsistency in continuous data acquisition on RPi

I am using the RPi to continuously acquire voltage data from an external ADC. I am using MCP3201 ADC (12 bit, 10k SPS) in a bit banging approach to get voltage data to Raspberry Pi and write it to a ...
1
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0answers
97 views

Why was my last AT command routine is not viewed in the output?

As I was using pigpio ,so that I can use the GPIO pins as UART or bit banging the serial. I am using a SIM900 gsm module. Here is the code: import pigpio import time import sys TX=23 RX=18 baudrate=...
1
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1answer
895 views

Using INT interrupt line on PCF8574 I2C 8-bit IO-expander on Bit-banged RPi GPIO?

I am planning to use a triplet of RPi GPIO pins as an additional bit-banged I2C bus on my RPi. This will be run at a lower than typical rate (and level-shifted via a 3.3 to 5.0 V I2C shifter unit) so ...
1
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1answer
130 views

Serial communication with two devices at once using pigpio?

I'm using the raspberry pi pigpio module to communicate with two other devices at once using two separate threads. The devices are connected to two different pairs of gpio pins. I need to adhere to ...
6
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3answers
10k views

How fast is GPIO+DMA? Multi I2S input

I want to connect multiple I2S ADCs to RaspberryPi and record multi-channel audio. I calculated that it requires copying GPIO input port to RAM at 3072kHz (or every 0.33µs). I want to do it using DMA. ...
1
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0answers
2k views

Problems Bit-Bashing an I2C Slave

I have a Pi B+ on which I'm trying to bit-bash an I2C Slave in C / C++ (code's pretty much C despite the fact I'm using g++ and .cpp files), utilizing GPIO 18 as my Clock and GPIO 17 as my Data. I'm ...
4
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2answers
3k views

Theoretical maximum data rate of GPIO pins

Is there a maximum data rate of the GPIO pins? I.e. if I wanted to bit-bang data through one of the pins, what kind of data rates could I achieve? Alternatively, what is the slew rate of a GPIO pin? ...
2
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1answer
2k views

Raspberry Pi on AVC-LAN / IEBus

I'm planning on using my Raspberry Pi in my car as an XBMC server. I'll be able to select songs/videos using the Android remote control app, but it occurred to me that it would be really neat if I ...
7
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1answer
5k views

How do I bit bang I²C master?

I've installed RPi.GPIO. It doesn't support I²C yet, but can I use it to bit bang I²C? I would just need the Raspberry Pi to be the master.