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wayoda / LedControl

An Arduino library for MAX7219 and MAX7221 Led display drivers
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more the 8 daisy chained #15

Open klarson18 opened 8 years ago

klarson18 commented 8 years ago

I would like to "daisychain" 10 7219 chips using ledcontrol.h but I am only successful with 8. Is this a software issue or a chip issue? Thanks

voneiden commented 8 years ago

As far as I know the packet size for the chip is 16 bytes, which has 8 bytes of data. That means a maximum of 7 no-op bytes and as such it is limited to a maximum of 8 chips.

https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf

klarson18 commented 8 years ago

Thank You for the response! Makes sense. Kyle Larson

On Fri, Apr 15, 2016 at 2:45 PM, Matti Eiden notifications@github.com wrote:

As far as I know the packet size for the chip is 16 bytes, which has 8 bytes of data. That means a maximum of 7 no-op bytes and as such it is limited to a maximum of 8 chips.

https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf

— You are receiving this because you authored the thread. Reply to this email directly or view it on GitHub https://github.com/wayoda/LedControl/issues/15#issuecomment-210591929

Sloaix commented 6 years ago

@voneiden

I do not think that's the reason.

voneiden commented 6 years ago

Yeah, I remember this was a wrong conclusion. More than 8 can be chained.

akhileshghanshyam commented 6 years ago

include.docx @klarson18 can u please send me the code to run the 8 matrix chain. because i have problem with my code
i have tried my best to make it run 8 matrix chain instead of 4. it will be very kind of u. my email id ghanshyam6298@gmail.com attached here is the code which i am using. this code is to chain 4 matrics. can you edit this code for me or if have any other code which can chain more than 4 matrices than please send me on above mentioned email id.

akhileshghanshyam commented 6 years ago

@voneiden can u please help me to chain 10 (8x8) matrices. I have code which is capable of running 4 matrices. i am trying to make it to run 10 matrices. but no succeeded yet. can you help me in any way. My email id ghanshyam6298@gmail.com . my hardware part is done and is working but in group of 4+4+2. the attached here is the code i am using. can you make desired changes in this code to make it run 10 matrices. if not 10 than at least 8. include.docx

DigaFabian commented 5 years ago

@klarson18 It is hardcoded in the LedControl.cpp file.

To get more than 8 matrices working go to your Arduino library folder, in my case it is located at:

C:\Users{Username}\Documents\Arduino\libraries\LedControl\src

There open the LedControl.cpp file with an editor like notepad++ and remove lines 50 and 51. This way I was able to chain 15 matrices, though I am not sure what the maximum amount of matrices is.