I'm a totally newbie and interested in physical programming like raspberry pi's. Is there any way to get the data which is intended to go to a "USB to TTL converter device" through USB(e.g. the output of a flashing software), read it and convert it to TTL using Python or C language? I mean something like:
Compiler --> avrdude --> Ethernet port of the compiler host PC --> Ethernet port of a Raspberry Pi --> Pins of the Raspberry Pi --> avr microcontroller
My question is about the code which I should run on the Raspberry Pi to do all the work required on that side. I'm guessing in this specific example it's possible to install avrdude on the Raspberry Pi and pipe the compiled code from the PC to the avrdude on the pi but I'm looking for a general solution that can be used with all microcontrollers, essentially turning the Raspberry Pi into a transparent, Ethernet connected, USB to TTL converter, either existing libraries or directions to how to write such code and where to read the documentations.
Edit1: There's a C language library called pigpio already installed on the Raspberry Pi OS and it can output UART. But I don't know how to read the USB data coming to the Raspberry Pi through its Ethernet port and convert it to UART data.
Edit2: I Changed USB port to Ethernet port since you can't connect two computers directly through USB. The data coming from the PC is still intended for USB to TTL converters since that's how avrdude and similar softwares are written(I guess it'll be "USB over Ethernet").
I've been trying to communicate different models of Roomba vacuum robots, 9xx and 6xx series, with a raspberry using the sci port of the roomba with no success. The sequence of steps have been:
connect pins 3 (rxd), 4 (txd), and 6 (ground) of the roomba port (5v) with a sparkfun logic level converter.
connect the output (3.3v) from the logic level converter to the gpio of the raspberry pi. Roomba Rxd to rpi txd, roomba txd to pi rxd, ground to ground.
connect rpi 5v to logic level converter HV and at the same time LV to gpio pin 1 (3.3v) for feeding high and low voltage required by the logic level converter.
disable serial console of the rpi
enable serial port hardware of the rpi
install and then open minicom in the rpi using this command
minicom -b 115200 -o -D /dev/serial0
place the roomba in the charging dock
I would now expect to read information about the charging process of the roomba in the minicom console but that's not happening.
Anyone knows if any of those steps is wrong?
My goals are to been able to read robots bump sensors in first place and then control movements of the robot from a pc using the rpi in between.
Thanks for any help.
Check this webseite. it's explaining exactly how to connect the roomba to the raspberry using an logic level converter
https://domoticproject.com/roomberry-surveillance-robot-roomba-raspberry-pi-zero-w-camera/
Raspberry Pi model: 3B
Running Raspbian OS
Recently I bought a Hyperpixel 2.1 round, which uses all of the GPIO ports. Whenever I plug the Raspberry Pi into my network switch, it is unable to connect to the network with the Hyperpixel attached. However, when I removed the Hyperpixel, the Ethernet capability came back.
I'm fairly sure it's a software issue given that there shouldn't be any problems with running all gpio pins in addition to Ethernet.
Is this a quirk with the Raspberry Pi that it doesn't like having all GPIO ports occupied as well as Ethernet? And how would I potentially go about fixing this, perhaps through command line or in the boot config?
I am currently working on a project that involves communication between a PLC , Raspberry Pi 4 and a BMS (Battery Management System) system on a battery.All three device use RS485 for communication using minimalmodbus via python on the RPI.
The Raspberry pi has a generic CAN/RS485 HAT (similar to this : https://www.waveshare.com/rs485-can-hat.htm)
Currently I am able to communicate with the PLC to receive and send data from the RPI with the PLC as a master and the RPI as a slave.
As per my understanding , in order to read data from the BMS using the Pi, the RPI has to be a master. But in this case, as the RPI is a slave to the PLC, and the PLC cannot be used to read data from the BMS.
I would like to know if it is possible for the RPI to function as a Master to the BMS when being a Slave to the PLC at the same time ?
Assuming that it is possible able to connect another RS 485 HAT to the same RPI and run separate scripts for each HAT.
How can we do serial communication using the raspberry pi with a python script to send/receive data to my laptop? If yes can we use the RS232 cable to connect to the TX/RX ports on the raspberry pi directly? If yes, what pins must be used from the RS232 cable? It would be help full if anyone can post a example python script?
Since my first aim is to send/receive data to the laptop to/from the raspberry pi, i'm using a RS232 to USB cable at both end to connect to the laptop as well as the raspberry pi.
RS-232/RS-485 to PC and USB to PC
For RS-232
1) Download Putty.
2) Buy a Serial Port RS232 to TTL Converter Module and a RS-232 serial cable for PC.
3) Follow the steps in Connection to a microcontroller or other peripheral on this
link. Actually read the whole thing for better understanding.
4) Power your converter module with either 3.3V (pin 1) or 5.0V (pin 2), connect Rxd pin of the module to Rxd (pin 8) on Rpi and Txd pin to Txd (pin 10) on Rpi.
5) Connect your RS-232 (from PC) cable to the converter module
Now you are ready to do some coding in Python. But before that make sure that you have the library called serial for python to create the communication. You can easliy get it via terminal by typing sudo apt-get install python-serial. Also you will see the baudrate in the code is 7200. It could be less or more depending on the synchronization. Also make sure that baudrate should be same in putty and COM1, which is the port that RS-232 is connected to your PC. You can check and set it from device manager in Windows. By the way, timeout is the time gap between each message you are receiving.
In case you can't run the code from idle (that happens for some libraries), do it in terminal. For that go to the folder where you keep your python code and type python name.py.
import serial
import time
def readlineCR(port):
rv = ""
while True:
ch = port.read()
rv += ch
if ch == '\r' or ch == '':
return rv
port = serial.Serial("/dev/ttyAMA0", baudrate = 7200, timeout = 2)
while True:
rcv = readlıneCR(port)
port.write("I typed: " + repr(rcv))
print(rcv)
For USB serial to PC
You have two options
First, you can buy a USB dongle for RS-232/RS-485 so that you would not use GPIO pins. But it is better to get a USB hub for all mouse, keyboard and dongle.
Second and easier, you can buy a FTDI USB to TTL converter and use GPIOs to have a serial communication with Rpi. The code for this is exactly the same the one with above. Connection for this is easy.
Module -- Rpi
Txd -- > Txd
Rxd -- > Rxd
Gnd ---> Gnd
Are you trying to issue commands to the Raspberry Pi? (like a console?) I would suggest a plain jane 3.3V FTDI cable. You can get them from Digikey or Sparkfun. Note: the Raspberry Pi runs on 3.3V so you must be sure that anything you connect to it is running 3.3V or has a level shifter. See more information about level shifters here. (go down to the Logic voltage levels section)
First, you need to make sure that Raspbian has released the serial console. You can do that with the script located here.
If you're more interested with communicating with other devices then maybe the following suits you:
Do you have an Arduino? You can run a simple test by putting this sketch on your Arduino:
#define SERIAL_BAUD 115200
void setup() {
//Init serial connection
Serial.begin(SERIAL_BAUD);
Serial.setTimeout(1);
}
void loop() {
if ( Serial.available() ) {
byte type = Serial.read();
Serial.write(type);
}
}
And wire it up using the following diagram:
Note: make sure you don't connect a usb cable to the Arduino. It will be powered by the Raspberry Pi.
You can then install and run screen. Screen is a dead simple way of connecting to a serial port.
apt-get install screen
Then run the following:
screen /dev/ttyAMA0 115200
The screen will show up blank. But, when you start typing you will notice that the characters you're writing are getting looped back to your terminal.
Note: If the screen is still blank you should double check the connections (power led on the Arduino is a good thing to check).
When in doubt you can see my whole example here.
The Raspberry Pi's serial port uses 3.3v logic; RS232 uses 12v, so a level shifter would be needed to use those pins so you cannot use RS232 directly.
Serial interfacing in Python using the PySerial module (http://pyserial.sourceforge.net) it is pretty straightforward to send and recieve data. There are examples in the documentation, but essentially to send data:
import serial
port = serial.Serial(portname, baudrate, timeout)
port.write("message to send")
port.close()
It depends what you're doing with the data and what sort of data you're recieving to decide the best way to recieve data, but a very simple example:
import serial
port = serial.Serial(portname, baudrate, timeout)
data = port.read(numberofbytes)
print data
This simply waits until the number of bytes specified has been retrieved or the timeout value is reached.
You can use port.inWaiting() to return how many bytes are currently in the buffer.
you should install python library for serial drivers. you can not use rs232 directly, instead you can use a max232 chip in between rx(gpio15) tx(gpio 14) pins and your usb to serial converter. or you can use usb to ttl serial cable from adafruit. here is the link for setup : http://learn.adafruit.com/adafruits-raspberry-pi-lesson-5-using-a-console-cable/overview
Serial Communication in Raspberry pi.
There are plenty of options for serial communication
Use Visual GDB Plugin in visual studio and deploy code remotely in raspberry pi
and loop back the txd and rxd pins and check if the send message is received or not.
If you are familiar with java Install pi4j and in the example folder there is a sample program , compile and run using terminal. and check the output.
if you are connecting using RS232 and Max232 , please note that uses 3.3 volt not 5 or 12v. , it may burn your board.