Hooking up RS232 to a ATTINY84

Discussion in 'General Electronics Chat' started by AgentSmithers, Jan 27, 2011.

  1. AgentSmithers

    Thread Starter Active Member

    Jan 14, 2011
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    Hi guys, Anyone have any documentation on hooking up a Microcontoller in general to a RS232 cable from the computer, it dose not have to be just for teh ATTiny84, but I'm stuck on a stage on what I need to look for on a chip and where to put the wires like TX and RX. I got the datasheet of the ATTiny84 and it tells me all of them are inputs and I'm just not sure on how to take the next step and if I do know where to plug in a wire I just would like to know why there and what to look for on other units if I wish to explorer other options or other Microcontollers.

    Does anyone know a good programming board for the ATtiny84 that does flashing and Debugging at the same time so I dont have to remove it from the breadboard? Thanks!!!
     
    Last edited: Jan 27, 2011
  2. arthur92710

    Active Member

    Jun 25, 2007
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    1
    You will need a MAX232 chip. The ATtiny is 0-5v and the signal from the pc is -15-15v.
     
  3. AgentSmithers

    Thread Starter Active Member

    Jan 14, 2011
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    I got one I completely understand that part, now I'm stuck on where to write the wires coming from the Max3232 chip to what pin on the Attiny84 and why?
     
  4. arthur92710

    Active Member

    Jun 25, 2007
    307
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    You could probably connect it to any pin, not ground or voltage, and modify your program.
    Im not sure if the ATtiny84 has built in serial hardware, but if it does and you choose to use it, it has specific pins that are used. Give me a few minutes and I will find out.
     
  5. AgentSmithers

    Thread Starter Active Member

    Jan 14, 2011
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    Right now I have the RX and TX hooked to up two random pins besides ground, Power and reset. and I'm using AVR Studio 4. I cant seem to get the Darn IDE to detect my ATtiny84 for the life of me on the correct COM port.
     
  6. arthur92710

    Active Member

    Jun 25, 2007
    307
    1
    Uhhh, what are you trying to do? If you are trying to write your program to the chip with a serial cable and max232, afaik it wont work.

    The pins for hardware serial are 7(SDA) and 9(SCL). Page 117 of the datasheet.
     
  7. AgentSmithers

    Thread Starter Active Member

    Jan 14, 2011
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    Why would it not work if you dont mind me asking?
    Just want to double check are you looking at this PDF? http://www.atmel.com/dyn/resources/prod_documents/doc8006.pdf
    I have the ATTIny84-20pu
    Thankyou for your help so far.
     
  8. arthur92710

    Active Member

    Jun 25, 2007
    307
    1
  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    I'd suggest staying away from DIY programmers on any uC platform. Too much frustration for just starting out.

    Try the AVR MKII Programmer for Atmel devices or the PICKit 2 or PICKit 3 if you want to try out the Microchip PIC line. Atmel AVR and Microchip PIC are the two major players in the hobbyist uC area.
     
  10. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Is your goal of connecting the ATTINY84 to your PC aimed at programming the ATTINY84? If so then I would echo the recommendation by others that you purchase an AVRISPMKII programmer. Once you have the tools for programming the ATTINY84 then you will be able to tap into its power.


    hgmjr
     
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