Go Down

Topic: Large button/led board. Multiple SCL-SDA connections (Read 859 times) previous topic - next topic

raschemmel


Moris526

Sounds lije you need a faster MCU
That would be a straight foward problem to solve.
Last question.
Communication via i2c is only one way at a time right?

raschemmel

#32
Oct 10, 2020, 03:12 am Last Edit: Oct 10, 2020, 03:17 am by raschemmel
It's bidirectional but not duplex (not simultaneously bidirectional)

I know it's too late but when you decided to run
32 of those boards you should have asked yourself "Hey, is this even possible ? And if so, what kind of issues will this cause ? Is an Arduino even fast enough ?
I would have emailed the manufacturer with your
proposal to do a feasibility study which is the
first step of any engineering project.

Moris526

It's bidirectional but not duplex (not simultaneously bidirectional)

I know it's too late but when you decided to run
32 of those boards you should have asked yourself "Hey, is this even possible ? And if so, what kind of issues will this cause ? Is an Arduino even fast enough ?
I would have emailed the manufacturer with your
proposal to do a feasibility study which is the
first step of any engineering project.
I know.
I pay the price for my axiety. The boards have 32 posible adresses, so I asumed It was ok to jump in.
This is my first engineering project and Im learning by the minute.


Thanks for the help!!! I`ll let you know if i succede !!

raschemmel

Quote
The boards have 32 posible adresses
Don't tell me you have them all running with the same address !

Moris526

Don't tell me you have them all running with the same address !
:D  Haha . No, no. I learnt a few things along the way.
MCU Speed seems to be a fitting candidate for an answer to all the evidence.  I will try with Arduino Due. Plus, i can make use of the 2 i2c ports. I have the large 32 units main board, and a 1 unit control board, so I was using an Arduino Mega and an Arduino uno. Not the neatest proyect you will see....but im wiser now.
Now Im diving in using both ports work at the same time

raschemmel

#36
Oct 10, 2020, 04:08 am Last Edit: Oct 10, 2020, 04:16 am by raschemmel
Quote
The Raspberry Pi Zero and Zero W use the same Broadcom BCM2835 SoC as the first generation Raspberry Pi, although now running at 1 GHz CPU clock speed.
Quote
MCU Speed seems to be a fitting candidate for an answer to all the evidence.
I still think your resistor pullups are borderline. 
Quote
Each module has level shifters with 10k pull up resistors, plus the one from the Mega,
that's a combined pull up of ~300 ohm...


Quote
My question is : Would it help if I make multiple conections of the SCL and SDA cables at differente point
More wiring is more wire capacitance, so I think a bad idea.

What speed is the TWI at. default 100kHz or high-speed 400kHz.
Does the code allow you to lower the I2C speed.?
You need the 400kHz speed. Read up on how to do that.
Then get a screaming fast MCU.
You know, something like they use in the Sidewinder air to air missile.



Moris526


Wait!

Dont you think Arduino due is fast enough?? Is 5 times faster than Mega....

I already bought one !!! haha Told you about my axiety right?

raschemmel

Really ?
The Rasoberry Pi is 62.5 times faster.

Moris526



Crap...

Its much smaller too.

But I already kind of get the Arduino IDE and code... And its a little bit more expensive......

damn doubt




raschemmel

#40
Oct 10, 2020, 12:07 pm Last Edit: Oct 11, 2020, 07:36 am by raschemmel

Moris526


The link is corrupt.

What is in that link doesnt work with Arduino Due? I canceled the purchase, not decided yet.

Thank you for the atention. Really appreciate it. 

What is your name? 


raschemmel

#42
Oct 11, 2020, 05:43 am Last Edit: Oct 11, 2020, 07:36 am by raschemmel
Sorry, I'm not sure what you meant.
You have a Mega but haven't teied 400kHz I2C yet?
You ordered a Duo ?
Have you isolated the problem ? (yes/no) (to either I2C, MCU Clock Speed, or Pullup Resistor issue ?
If you haven't configured the Mega for 400 kHz I2C communication then you really don't know what the issue is.

Moris526

#43
Oct 11, 2020, 06:49 pm Last Edit: Oct 11, 2020, 06:53 pm by Moris526
Sorry, I'm not sure what you meant.
You have a Mega but haven't teied 400kHz I2C yet?
You ordered a Duo ?
Have you isolated the problem ? (yes/no) (to either I2C, MCU Clock Speed, or Pullup Resistor issue ?
If you haven't configured the Mega for 400 kHz I2C communication then you really don't know what the issue is.

I try 400khz i2c with the mega with no luck.
Im pretty sure is MCU speed...
Question:  When I press a button on the grid, the data going to Arduino is just of that button state?  or of the state at that moment of all the buttons?

If Arduino recives all the states, that would explain why the bigger the board, the bigger the issue.

raschemmel

Large Button document

Neo-Trellis Overview

According to Adafruit, everything should work perfectly with your current setup.
Did you try the Adafruit Support Forum ?

Did you follow the Adafruit PDF document ?

Go Up