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LMP91300: SWIF Inquiry

Cedrick
Expert 8270 points
Part Number: LMP91300


Hi,

Good day.

Our customer is using the LMP91300 and they have inquiry about the single wire interface. Kindly refer to their inquiry below.

""I'm using LMP91300 sensor but GUI software tool not works so I will connect MCU to Sensor to program and read registers What is the used single wire interface for this sensor? Is it SPI protocol or UART protocol? How to connect MCU With this Sensor ?

• e2e.ti.com/.../lmp91300-serial-interface-connection
• /cfs-file/__key/communityserver-discussions-components-files/1023/LMP91300SWIFEVM-User-Guide_5F00_2013_2D00_10_2D00_09.pdf

Ilooked for these Threads , datasheet and board User guide I couldn't understand How Single Wire interface(one wire) is used for programming and the Two wires are connected to MCU(MSP430) SWIFMISO -SWIfMOSI ...Please can you help me in this Point How I can connect Sensor to MCU?
Datasheet for the hardware between sensor and MCU is not enough""


Can you please help on this matter? Thank you.

Regards,

Cedrick

  • 0
    TI__Mastermind 40295 points

    Cedrick,

    The MCU transmits to the LMP91300 via the SENSE2/SWIF pin, and it receives data via the same wire on the LED pin. The details are given in sections 7.5.2 and 82.2.215 of the data sheet. The TX/RX functions are shared on the single wire. 

    I could not find another reference to the 2-wire interface, but I think it refers to the loop connections mentioned in the first paragraph of section 7.5.2.

    Please let me know if you have any questions.

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    TI__Expert 8270 points

    Hello John,

    Thank you for this information.

    Our customer has feedback this:

    The sensor Pins are three pins Vcc(6-40V) , Gnd and Load pin ...Will I use Load pin to Transmit data from MCU to Sensor and receive it from Led ? Texas says there is Extension board with sensor it has Two pins(MISO - MOSI) connected to MCU and one time Programmable I don't understand Datasheet not enough
    Can you check these files Please ?

    Extension Board has Processor(MSP430) and some integrated circuits(ICs)...Texas says Data is transmitting cross DC(Vcc) pin and receiving it cross GND pin
    Will I connect sensor to MCU using single wire interface only or I have to use Extension board with sensor ?


    Looking forward to your inputs.


    Regards,

    Cedrick

  • 0 in reply to Cedrick
    TI__Mastermind 40295 points

    Cedrick,

    I will have an update to your questions by COB tomorrow.

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    TI__Mastermind 40295 points

    Cedrick,

    The master device talks to the LPM91300 by superimposing a pulse train on the LMP VCC line as described in section 7.5.2 of the data sheet.
    Conversely, the master device reads back from the LMP91300 by monitoring current pulses from the LED pin, also described in section 7.5.2. 

    I'm not sure if the extension board you mentioned supports this protocol. 
    The LPM91300 product folder references a SPIO controller board in the form of a user's guide.
    Is this the extension board you mentioned?
    If it is, it is meant to work with WaveVision software available for down load from here,
    A WaveVision driver installation guide and user's guide are also available which may have the information you are looking for.

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    TI__Expert 8270 points

    Hi John,

    Thank you for this explanation.

    The customer has replied this.

    "Extension board is LMP91300SWIFEVM board
    I don't understand connecting between the MCU , LMP91300NPN sensor and LMP91300SWIFEVM board
    Can you explain me The hardware between MCU and LMP91300NPN sensor ?
    will I use LMP91300SWIFEVM board in Hardware ?    "

    It seems that the LMP91300SWIFEVM  is obsolete already. Do we have document that the customer can follow?

    Thank you.


    Regards,

    Cedrick

  • 0 in reply to Cedrick
    TI__Expert 7599 points

    Hi Cedrick,

    John is out on timebank. John will provide an update on this on Wednesday. Thanks. 

  • 0 in reply to Arjun_Prakash
    TI__Mastermind 40295 points

    Cedrick,

    There doesn't seem to be any additional info on the LMP91300 EVM, beyond what is in the data sheet.
    Has the customer tried searching our E2E forums for the information they are looking for?

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    TI__Expert 8270 points

    Hi John,

    Yes, they have tried to search in E2E. Also, I've shared some links that might helped him but still they are not successful.


    Regards,

    Cedrick

  • 0 in reply to Cedrick
    TI__Mastermind 40295 points

    Cedrick,

    My management has confirmed the EVM is no longer available. 
    Please let me know if there is anything else that can be done to help the customer.

    Regards,
    John