custom board using arduino bootloader

So what I'm looking to do is create a custom board for my application. due to some of the components involved (serial lcd) and ease of programming I'd like to be able to interface/program it using the arduino environment. My thought is to essentially take all of the components of an arduino pro mini without changing them at all and include them with the other components I need all on one board. Is there any problem with doing that? The computer should still communicate with the board as if it were a mini and can be programmed accordingly correct?

I have heard it might be necessary to not have the serial lcd connected to the tx rx pins when uploading code to the board. Can anyone confirm that one way or the other?

wolverineairsoft:
So what I'm looking to do is create a custom board for my application. due to some of the components involved (serial lcd) and ease of programming I'd like to be able to interface/program it using the arduino environment. My thought is to essentially take all of the components of an arduino pro mini without changing them at all and include them with the other components I need all on one board. Is there any problem with doing that? The computer should still communicate with the board as if it were a mini and can be programmed accordingly correct?

I have heard it might be necessary to not have the serial lcd connected to the tx rx pins when uploading code to the board. Can anyone confirm that one way or the other?

You don't want the serial LCD attached to the arduino when uploading, because the serial pins are used during uploading. When you upload the code, it is possible that some of the bytes being sent over the serial lines could be recognized as commands by the LCD, which could damage it (setting the backlight to the highest value, and overtaxing the powersupply for example). You can use the Software serial library to get around this (by making a regular digital pin to a serial pin).

Thanks for the info. I'll look into doing that. it would be nice to be able to program it with everything attached if necessary. But as far as the basic idea of using the parts on on a larger board and programming it as an arduino, there's no problem with that correct? I guess I'm not super clear on the interface between the bootloader and the hardware. I thought the bootloader is only on the chip so as long as all the external parts (clock etc) that it needs to reference are there, it shouldn't care if there are other parts attached. As long as they don't interfere with the programming itself. I should have enough pins to leave the tx rx pins empty if I can use other pins for the serial lcd.

Thanks!

wolverineairsoft:
Thanks for the info. I'll look into doing that. it would be nice to be able to program it with everything attached if necessary. But as far as the basic idea of using the parts on on a larger board and programming it as an arduino, there's no problem with that correct? I guess I'm not super clear on the interface between the bootloader and the hardware. I thought the bootloader is only on the chip so as long as all the external parts (clock etc) that it needs to reference are there, it shouldn't care if there are other parts attached. As long as they don't interfere with the programming itself. I should have enough pins to leave the tx rx pins empty if I can use other pins for the serial lcd.

Thanks!

I am not familiar with the Arduino Pro mini, but it would appear that you would need a USB to serial adapter to program it using the Arduino IDE software. If I were you, I would base the board off of something easier, like the Arduino Uno. The Arduino Pro mini uses surface mount components, which are difficult to solder unless you are set up for it. You might want to take a look at the Arduino Standalone article in the playground: Arduino - Home

I would if I had enough space. I'm used an uno for my first mock up, and am working on a nano for my full prototype. I plan to program it using the mini usb adapter. I have another question. I'm sure I'm missreading the brd file, but it appears to me that not all of the gnd pins are connected. http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Dev/Arduino/Boards/Arduino-Pro-Mini-v13.zip

What am I missing?

Perhaps my free version of eagle is not showing a layer?

wolverineairsoft:
Perhaps my free version of eagle is not showing a layer?

I don't have Eagle installed on this computer, but I do know that (at least on the DIP, probably the SMD ones too) the grounds on the Atmel chip are connected internally.

Sorry I have so many questions...I'm gonna have a lot more. this is the lcd screen I'm looking at:
http://www.newhavendisplay.net/index.php?main_page=product_info&cPath=3_111&products_id=1829

Could run a naked ATmega168A and use the internal clock at 8Mhz to communicate with the screen? I could run the whole board at 3Volts. I understand there may be baudrate limitations but I'm talking about pretty limited amount of data. (max or 32 characters) If I understand it correctly I could treat that as a lilly pad for programming purposes. Other than the lcd all i'm doing is taking 2 switch inputs and controlling and opening and closing some transistors.