If I connect more TX to a single RX, there might be disturbs or anything else, so to avoid it I just open the circuit placing a diode after every TX and bring +5V to the RX with a pullup resistor.
#Pa035 serial communication protocol free
The advantage of using SoftwareSerial is that you leave HardwareSerial free for debug messages.įrom the changes I made I assume RX is normally HIGH and when data is incoming there is a PWM, or just a sequence of LOW and HIGH states. The signal on the master's TX line will be received by all of the slaves so you may need to include an ID in each message if a slave is to identify which messages are intended for it.Īll of this is valid whether you use HardwareSerial or SoftwareSerial on the master. Of course you must also arrange your programs so that only one slave talks at any one time. Then the slaves will be able to pull the line LOW when they transmit data.
And, because the master expects the incoming signal to idle HIGH you need to put a pullup resistor (about 4700 ohms should work) on the RX pin of the master. The problem is that the TX lines from the slaves idle HIGH so you need to prevent that from getting to the RX pin on the master by inserting a diode in the TX line from each slave. However you will need some extra components to prevent the signals coming from the slaves interfering with each other. You can connect one master to several slaves using a single serial port on the master. I could program each arduino like: I read the serial data when available, if the address read is mine (egs the Master when data is sent from Arduino Station Slave to Master) I process it and reply with the slave address, meanwhile if the address isnt mine (egs another arduino station reading data from another arduino station) I just send it again as it is If Arduino Station n1 detects a card, it will send to the Master the Address+the Id of the card (eg: 00255255255255: where 00 is master address and 255255255255 is the 4 bytes ID)
#Pa035 serial communication protocol series
Is there a way to connect all the Serial ports in series one to the other and send data with an address like this? The master arduino will decide if the card is allowed or not and will reply to the Arduino station.
Whenever a tag is detected by the sensor, send the ID of the card is sent to the master (another arduino). The idea was of some arduino stations with a RFID module each. I know Arduino Mega has several Serial Ports that could be used, but in my case I just have an atmega328 with one only port (rx and tx). Hi guys, I need a way to have 3 or more arduinos in comunication with only one serial port.