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Topic: Question about LCD Shield (Read 552 times) previous topic - next topic

monti73

Hi to every one. I don't speak english, I hope i make my self clear.
I have an LCD with Keypad Shield, it works fine. But I also have a home made shield for my project. The LCD shield use the pin 9 (which is pwn) as "enable", but I really need that pwn pin for my project, so I can't use both shields at the same time...  My question is if someone know if I can cut the pin 9 of the shield and connect it directly to 5 volts so the shield is always enabled and I can use the 9 pin for my shield.

Is this possible without burning something??

Thanks to everyone!  XD

Nick_Pyner

It might be simpler to leave the LCD shield alone and use another pin on the other shield.  LCD shields typically provide points for wiring on pins D0-D7 with this sort of thing in mind, but I have never seen a point on pin 9.  This means that you would have to wire to the top of the pin. I had a clash between LCD and the main board but I kept the LCD pin and ran a jumper on the intervening proto shield.

monti73


It might be simpler to leave the LCD shield alone and use another pin on the other shield.  LCD shields typically provide points for wiring on pins D0-D7 with this sort of thing in mind, but I have never seen a point on pin 9.  This means that you would have to wire to the top of the pin. I had a clash between LCD and the main board but I kept the LCD pin and ran a jumper on the intervening proto shield.


HI Nick, thanks for your answer! But I'm a little bit eager so I've already made what I ask for ahah, everything works fine, no smoke so far. Now I use the pin 12 as the enable of the shield and change the definition of the lcd in the code.

Thanks anyway!  :)

liudr

#3
Feb 02, 2013, 02:04 am Last Edit: Feb 02, 2013, 02:06 am by liudr Reason: 1
Don't wire enable to 5V! Arduino needs that to tell the lcd to read from the bus. Cut the pin on the bottom of the shield and simply wire it to an unused pin.

You explained yourself perfectly clearly in English. It is often not an issue with the language but rather the personality. Speaking the language doesn't translate into clearly stating a problem. You did this well, English is always secondary.


Nick_Pyner



It might be simpler to leave the LCD shield alone and use another pin on the other shield. 


HI Nick, thanks for your answer! But I'm a little bit eager so I've already made what I ask for ahah, everything works fine, no smoke so far. Now I use the pin 12 as the enable of the shield and change the definition of the lcd in the code.


Hi Monti.

OK.
I think in principle it is best to leave the store-bought stuff alone an make the modifications on your own stuff but, if it works, it works!

Having said that, I submit that pin 12 is a poor choice you may regret later.  This is typically used for MISO on the SPI bus, and best left for that purpose.   Pins 2-10 are usually all PWM  and equally convenient.

I got real value making up a colourful Excel spreadsheet of the pin allocations, enabling me to (hopefully) plan for everything.  This particularly applies if you home-brew proto shields!

liudr

UNO only has 6 PWM pins, not all 2-10 are pwm. The op should also consider whether tone() is needed in the project, which breaks two PWM channels.

monti73

Thanks to everyone for the answers! I've finally modified both the LCD shield and my own shield and everything is working OK. I've Changed the enable pin to the pin 12 and also another pin which is using my lovely pwn pins  :smiley-mr-green:.

As nick said it would be better to modify my shield instead of the LCD, but the LCD is destinated to this project so I did it anyway.

Thanks again! I'll share my project when its finished

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