how do i send I2C transmissions on the arduino board?

Projects Programming
1

hi everyone

first off im new here, so hello!

secondly, i have to begin some I2C transmissions with the Arduino board, and i have no idea how am i supposed to do that. i have been looking at youtube tutorials and stuff for the past days and all of them are using another device with the arduino board.

in my case, i have to send I2C transmissions on the same board i have and make the LEDs on there light through I2C transmission. after this is done, we are gonna move on to adding and ISSI board perhaps, but for now i have to send I2C transmissions on the same board.

anyone know a good source where i could find code regarding this?

thanks!

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2

hi

is it possible to have some kind code to send I2C transmissions on the same single aruino board and light the LED's on the board as a way to show the transmission code works?

3

Sure, can't see why not.

4

great, do you know how would i be able to approach this? if there are any references to code examples doing that perhaps?
the only thing i could find is transmission code between two arduinos.

6

the only thing i could find is transmission code between two arduinos.

Are you trying to send from an Arduino and receive on the same one ?

7

UKHeliBob:
Are you trying to send from an Arduino and receive on the same one ?

yup. and to know that the transmission worked, the LED's should light

9

Delta_G:
I don't know how that would work on I2C since it uses the same wire to both transmit and receive data. I don't see how you would possibly sample the line at the same time you are transmitting on it.

What is the purpose of this experiment?

well its to figure out how I2C transmission works and the code for it before we move on and connect it to an ISSI board (IS31FL3732) with two arrays of 72 LEDs, for a total of 144 LEDs.

10

moderator: Cross-posts merged (please keep one thread per subject (or even project)

11

robtillaart:
moderator: Cross-posts merged (please keep one thread per subject (or even project)

ok sry about that. i just didnt know which thread is better to post in in regards to my topic

12

I merged them into this one as here there was an active discussion ...

13

Have you looked at Mr. Gammon's offerings?

14

masterofcatastrophe:
yup. and to know that the transmission worked, the LED's should light

You can't really do that... You cannot have an I2C transaction without both a master and a slave device. I2C uses the same wire for both directions, and requires the slave device to acknowledge each byte... I don't see how you would do this and have the result behave enough like a real I2C device to be a useful test.

Why not just print the data you're going to send over I2C to serial, so you can verify manually that it's sending the data you think it is? If you're using a known working I2C library like Wire, you can have some degree of confidence that it's not mangling the data. Which is good, since I don't have a good way to do that.

I've written libraries or modules for a number of I2C devices - I've never felt I needed something that listened to the data on the I2C bus.

15

If you have 2 Arduinos, you can connect them together for testing, one as an I2C Master and one as a Slave.

16

i see. so you cant send/receive on the SAME single arduino. it has to be done with another device?

cause eventually the plan is to connect with the ISSI IS31FL3732 compact driver that supports two arrays of 72 LEDs (so 144 total).

17

Just get yourself a cheap I2C RTC or display or something to play with. Or use another Arduino, as I suggested.

18

well ima have to play with the ISSI LED driver eventually so i already have another device lol. i just thought i could first talk through I2C with the arduino itself in itself, and make those LED lights on it light