Using RGB shield with 40x4 displays
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Using RGB shield with 40x4 displays

by kobe1 on Thu Nov 15, 2012 4:54 pm

I am using a 40x4 LCD display on my Arduino Mega. I noticed that pin 26 on the i2c controller (data GPA6) is not being used. It would be easy to jumper that pin from the ic to use as enable 2 (the second enable line for the lcd 40x4 display). Is it possible to add a second enable (i.e. enable and enable1 in the liquidcrystal.h or .cpp files) and set up mapping to a pseudo pin to enable the 2 pins for the larger lcd. This of course would have to be an external hardware jumper for now but something that might be considered (would only have to add a trace to the pcb) for futures in the rgb board design. Would ladyada or anyone care to look in their spare time (yeah right!) and see if this could be added as I am not that proficient in C (forgot too much - if I ever knew). I looked in the code and saw where enable is stated but not able to follow logic all that well. It seems to me if one jumpers the unused pin hardware wise and has the changes in the .h and .cpp files things would work flawlessly. Of course with the understanding that one would have to use a ribbon cable to go from the rgb shield to the display. I am supposing that this would all be external wiring by the user since the pinout for the displays are most likely different. But this could work great as a standalone setup for a larger display. Thanks for listening (reading) and keep up the good work.

kobe1
 
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Joined: Tue Jul 10, 2012 5:11 pm
Location: North Texas

Re: Using RGB shield with 40x4 displays

by kobe1 on Thu Nov 15, 2012 5:03 pm

Kobe1 here again. I should add I am using the LiquidCrystalNew library at present as this does allow for 40x4 displays. Using a Newhaven NHD-0440-ATMI-JT at present and is working great using 8 pins on the Mega for control. Just would like to use i2c and the Adafruit RGB shield. Thanks all.

kobe1
 
Posts: 4
Joined: Tue Jul 10, 2012 5:11 pm
Location: North Texas