Push-Pull vs Open drain interfacing to Arduino

I am looking at a module that has a serial interface (rs232 type) that has two modes available for the Tx and Rx pins:
"Can be configured as open-drain or pull-up input."

I want it to communicate with an Arduino so, are either of these modes compatible with an input or output of the Arduino or do they require additional circuitry?

Something like this?

Another example calling out Arduino.

That what you want?

Ron

If you go to eBay and search for: "arduino rs232" I got over 600 hits. There are some that are less then a buck using a Maxim chip. The best thing is to look at them and determine (you may have to read data sheets) to get the output you want. The Max chip is comparable with the Arduino. Also Rx goes to Tx and Tx goes to Rx.

The MAX232 chip can do the conversion from RS232 to TTL Serial for you.

Thanks guys but I didn't meant rs232 literally, I was only trying to distinguish the serial communication from say SPI which some also call "serial".

The input/output of these modules are at 3.3 and 5 volt levels (but otherwise rs232 like as in characters at various baud rates) but have the option of push-pull or open drain.

How would I connect these modules to an Arduino (either 3.3v or 5v as required) pins so that I can communicate with these modules using push-pull or open drain?

lemming:
I am looking at a module that has a serial interface (rs232 type) that has two modes available for the Tx and Rx pins:
"Can be configured as open-drain or pull-up input."

Why don't you post a link to the product? Makes it easier for everyone to advise.

http://www.ebyte.com/en/product-view-news.aspx?id=484

Hi,
Why don’t you simply say;

SX1268 Lora Unit

google
arduino sx1260 lora

Have you even looked at the manual available from that site?

Tom… :slight_smile:

The manual states RX is an input and can be open-drain or pullup input. That’s wrong, its an input, it means it
can be an input or an input with pullup.

The TX is push-pull or open-drain.

However the manual says nothing about how to configure them…

You’ll have to experiment. Try a 2k2 resistor in series with the connections to limit current and probe with 'scope or multimeter to see what voltages are present.

The manual is inexcusably vague about voltages of the logic signals.

In general push-pull outputs are better if both devices share supply voltage. Open drain is simpler in mixed environment. Both are easy to use with Arduino.

Thanks Guys.

@ Smajdalf

Both are easy to use with Arduino.

I was more interested in how, rather than how easy it is. Please would you provide a sketch of how you would connect between the Arduino Rx pin and the Tx pin of the transceiver using the transceivers open drain or push-pull output and the wiring between the Tx pin of the Arduino and the Rx pin of the transceiver using open drain or pullup of the transceivers input.

Cheers

Hi,
Why don't you google.
Why are you so worried about pushpull and open collector?

This site will tell you all about connecting an Arduino to a Lora unit.

Can you tell us your electronics, programming, arduino, hardware experience?

Tom.... :slight_smile:

lemming:
connect between the Arduino Rx pin and the Tx pin of the transceiver using the transceivers open drain or push-pull output and the wiring between the Tx pin of the Arduino and the Rx pin of the transceiver

Normally I'd use a wire for that.

If needed a voltage divider for level shifting from high to low; the other direction normally doesn't need level shifting.