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MSP430G2 Launchpad with TRF7970ABP

Radiya Dhaval
Intellectual 490 points
Other Parts Discussed in Thread: TRF7970A

Hi TI,


I have MSP430G2 launchpad connected with TRF7970ABP and i follow the steps available in slab068.pdf for experiment to read the ISO14443A, ISO14443B and ISO 15693 tag. so right i am using TRF7970ABP_Demo code downloaded from TI site.

So, right now i am to able to read the ISO14443A tag from 3 to 5cm of distance from  TRF7970ABP but i want to read the tag from distance 10 to 15 cm. So, is it possible from software side to read the tag from distance 10 to 15 cm or any other solution is available in TRF7970ABP hardware.


Please give suggestions if any.

Thank you.

  • 0
    Guru 74080 points

    Hi Radiya!

    The TRF7970A has an adjustable output power which can be set by bit 4 in the Chip Status Control Register (0x00). But when running from 3.3V, the output power is only 33mW or 70mW whereas it could be 100mW/200mW when running at 5V. Unfortunately the MSP-EXP430G2 LaunchPad only provides 3.3V (about 3.6V to be precise) on it's headers. Maybe you can use the USB's 5V to power the device, but this might need some modifications.

    Dennis

  • 0 in reply to Dennis Eichmann
    Intellectual 490 points
    Hi Dennis,

    As per your suggestion, I have done some modification in hardware and give 5V power to the device and also changed the code as per describe in below link

    www.ti.com/.../slos743k.pdf page no 19 : Table 6-4. 5-V Operation Power Modes


    and the changes is,

    void
    Trf7970TurnRfOn(void)
    {
    u08_t write[4];
    write[0] = CHIP_STATE_CONTROL;
    write[1] = 0x21; // 5.0 VDC, Full power out
    //write[1] = 0x20; // 3.3 VDC, Full power out
    Trf7970WriteSingle(write, 2);

    }
    in trf7970.c file in TRF7970ABP_Demo code available with me , but the tag read distance is remains the same and the tag read at 3 to 5 cm of distance. So, if any other solution is there or if i am doing wrong, please give the right direction.

    Thank you.

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