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TM4C123GH6PZ: Interface with MAX1454 IC Single wire communication

Part Number: TM4C123GH6PZ

Hi,

I am interfacing my controller with Max1454 Signal conditioner IC. I want to communicate with the IC, but the device will support only single wire communication. Is it possible to use single wire communication with TM4c123.

If any one worked on single wire communication, Please let me know how we can communicate with TM4c123 using single wire communication method.

Thank you,

Alphy

  • There is no 1-wire peripheral on the TM4C123GH6PZ device like there is on the TM4C129XKCZAD device, but it can be emulated with a UART. You would need to tie the UnTx and UnRx pins together and then configure the UnTx pin as a GPIO input when the slave is responding. I suggest you put a current limiting resistor on the UnTx pin in case you accidentally have it still driving high while the slave is trying to drive low. The resistor should be large enough to protect the output buffer of the TM4C but small enough to guarantee good Vil levels when used with the 1-wire pullup resistor.  

  • Hi,

    Thank you so much for your quick reply. As per your reply I am planning to use UART pin for single wire communication, then my doubt is I need to configure the pins in UART mode(commands used for setting UART) or normal GPIO pin. One more doubt I am having is if I am setting the unTx pin as input when slave is sending data, then while writing data to slave I need to set the UnTx pin as output or every read and write I need to set the pin(UnTx) as input and output and no need to use UnRX pin.

    Thank you,

    Alphy

  • The UART TX pin will not automatically decode the serial stream received by the slave. I suggested you use two pins from the TM4C tied together, a UART TX and a UART RX pin. The UART TX pin is used to transmit from the master to the slave. Then the UART TX pin is made a GPIO input and ignored. The data from the slave is received and decoded by the UART RX pin. Every time the direction of data flow changes, you must change the UART TX pin from its UART mode to GPIO mode or back. Note that the UART RX pin will also receive the data being transmitted. Software can throw away those extra characters.

  • Hi,

    Thank you so much for your quick reply. Now I am busy with some other projects, so unable to test this. I understood about the changes I need to done on my software and hardware.

    Once again thank you so much for your help.

    Thank you,

    Alphy