Using the data logging shield with the 2.8" TFT V2 shield

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RobertGriffin
 
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Using the data logging shield with the 2.8" TFT V2 shield

Post by RobertGriffin »

Hi,
I'm trying to interface four laboratory balances to the UART serial pins on a Mega 2560 Rev 3 board. The data collection rate is minimal - a 20 character string from each balance once every 5 minutes.

I'd like to log data to the data logging shield to use the RTC feature to timestamp. I'd also like to display a graph of the data on the 2.8" TFT V2 shield. Is is possible to use both shields together?

If not, is it possible to write to the micro SD card on the 2.8" TFT shield - the Adafruit help for this shield indicates reading, but not writing, to this card. I'd sacrifice the timestamp if absolutely required.

Thanks for the help!
Robert

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adafruit_support_rick
 
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Re: Using the data logging shield with the 2.8" TFT V2 shiel

Post by adafruit_support_rick »

You can do it. However, you will have to cut a trace on the logger shield to disconnect the SD card chip select line (the trace is a thin strip of copper bonded to the board. It is underneath the blue coating. Make sure you cut all the way through it).
cut_logger_SDCS.png
cut_logger_SDCS.png (658.01 KiB) Viewed 312 times
This will disable the SD card on the logger. You can then read and write to the SD card on the TFT shield. To do that, set up the SD.begin call in your sketch with pin 4 as the Chip Select.

Also, make sure you get a set of stacking headers for the logger shield, so that you can stack the TFT on top of it.
https://www.adafruit.com/product/85

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wdickenson
 
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Re: Using the data logging shield with the 2.8" TFT V2 shiel

Post by wdickenson »

How about the other way around ? I would rather use the datalogger shield and not the TFT Shield ?
Thanks

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adafruit_support_rick
 
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Re: Using the data logging shield with the 2.8" TFT V2 shiel

Post by adafruit_support_rick »

You mean use the SD card on the logger instead of on the TFT? You can't really do that. Pin 10 is a conflict. You can't move it on the TFT, and you can't move it on the logger. The only solution I can think of is to cut it on the logger.

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wdickenson
 
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Re: Using the data logging shield with the 2.8" TFT V2 shiel

Post by wdickenson »

ugh.. so no jumper on TFT to cut ? ahh well. That limits it for my application. Thank you for checking

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wdickenson
 
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Re: Using the data logging shield with the 2.8" TFT V2 shiel

Post by wdickenson »

of course, in a blinding flash of the obvious, I could skip the shield and just not connect pin 4 ? or, cut the post on the shield so pin 4 is unconnected ? obviously the TFT tends to be the top .............. that should solve my problem. A bit crude but workable

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