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Topic: Newbie simple question need multiple a4a5 ports for project (Read 73 times) previous topic - next topic

DeanCC

Hello,
 I just recently got hooked on my Arduino.  Quick question. I would like to build a project that requires the BMP180 pressure sensor, the BN0055 orientation chip and the simple LCD display bar. I want to use the simplified LCD setup that minimizes the number of wires coming from the LCD display.  All three of these devices use the A4 A5 slots on the Arduino.I noticed that my Arduino is an R3 version and has SCL and SDA slots next to the AREF position. Can I use these devices together on the one Arduino board ? 

Many thanks
 

OldSteve

Which Arduino board?
And I'm surprised to hear that the LCD uses analogue input pins. Can't you select which pins it uses?
Please do not PM me for help. I am not a personal consultant.
And others will benefit as well if you post your question publicly on the forums.

Budvar10

If you look at the schematics A4/SDA and A5/SDA are interconnected. It doesn't matter which two you will use. It is I2C bus and you can hook more devices on it. Each device is accessed via its address which has to be unique.
Arduino clone with ATmega1284P

Budvar10

Which Arduino board?
And I'm surprised to hear that the LCD uses analogue input pins. Can't you select which pins it uses?
I'm guessing LCD with I2C and UNO.
Arduino clone with ATmega1284P

OldSteve

I'm guessing LCD with I2C and UNO.
Ha. Yeah, right. I've never used I2C with my UNOs. Just took a look.....
We live and learn. :)

Edit: I have an I2C LCD module on it's way now, so would have known this in a few days.  :smiley-red:
Please do not PM me for help. I am not a personal consultant.
And others will benefit as well if you post your question publicly on the forums.

DeanCC

Ah, yes , its an Arduino Uno board. I am just assuming that the board with handle to code for all the devices that I want to put on it simultaneously.  I see that I have to learn more about l2C and code writing. But at least I got my answer.  Gosh that was quick. Just beginning. Ok l2C bus and device addresses. Gonna start with my copies of PROGRAMMING ARDUINO BY Simon Monk both volumes and then onto Google searches.

Thank you

Budvar10

It should not be a problem to use I2C, it is quite simple. Arduino SW contains Wire library for I2C comunication. There are also examples for use. Your LCD, whether is original I2C or use some transceiver, there is a library for it. You just have to find out the address from the datasheet of LCD or IC which is on transceiver. Personally, I'm using LiquidCrystal library from Francisco Malpartida. It supports I2C and it's fast and small. BMP180 - look at: https://www.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf, section 5.2 for address etc.
Good luck
Arduino clone with ATmega1284P

Simpson_Jr


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