Two LCD Shield Kits - i2caddr
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Two LCD Shield Kits - i2caddr

by KE5QDA on Wed Feb 06, 2013 10:18 am

Hi,

I just bought two of the LCD Shield Kits and intend to use them both for a transceiver. I know it's a simple thing, but, how do I change the i2caddr? I want to use addresses 0x4 and 0x5 for the LCDs. Yes, I've already downloaded the software and it looks great, except for the address thing. I'm a newbie. :oops:
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Re: Two LCD Shield Kits - i2caddr

by adafruit_support_bill on Wed Feb 06, 2013 11:18 am

The base address of the chip is 0x20 and it has 3 address lines. That means the range of possible addresses are 0x20-0x27.

Since it was designed as a shield, the address lines are not brought out. A0, A1 & A2 are all tied to ground. If you are willing to cut traces on the board, you could pull one or more address lines high with a 10K resistor to change the address on one of the boards. You'd probably need to do a little hacking in the library to handle the address change as well.
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Re: Two LCD Shield Kits - i2caddr

by KE5QDA on Wed Feb 06, 2013 11:23 am

Thanks for the quick reply! That is just what I needed...I'll be back if I can't make it work. :wink:
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Re: Two LCD Shield Kits - i2caddr

by KE5QDA on Sat Feb 16, 2013 4:34 pm

I'm baaaack! The code doesn't seem to work for two reasons. 1. The address is defined in Adafruit_LCM2013.h and it is not easy to add another address without throwing everything off. 2. The code for making it work uses "lcd.action" code that won't work without an lcd library file and is also using "Serial" code that doesn't apply to i2c.

Do I just need to figure this out on my own, or, is there something easy to do??? When I compile, I get too many errors to troubleshoot and they are all related to "lcd" and "serial".
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