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Sleep mode issue in MSP430 with CC1120

Muhsin Atto
Prodigy 60 points
Other Parts Discussed in Thread: MSP430FR6989, MSP430FR5969, CC1120, ENERGYTRACE

I use MSP430FR5969 and MSP430FR6989 with CC1120 transceiver to build wireless nodes. Each of this component draws 1 micro Ampere in sleep mode.

I connect MSP430FR5969 with CC1120  and after I configure them, I put both in sleep mode and remove all jumpers to measure the current . I get about 170 micro Ampere instead of two micro Ampere as claimed in the datasheet.

Does this increment in drawing current  because some ports of MCU remain active (such as CS pin in SPI interface) to keep CC1120 in sleep mode.

I really appreciate any comment or reply help me to understand this issue.

Thanks.

  • 0
    TI__Genius 12315 points
    Hi Muhsin,

    Which LPM mode do you use of MSP430FR5969? Did you test the current consumption of MSP430FR5969 without CC1120 connected?
    For low power, the unused pin of MSP430FR5969 should be set to output low state.

    B.R
    Winter
  • 0 in reply to Winter Yu
    Prodigy 60 points
    I use LPM3 and I configured all unused pins to output low.
    When I measured the current drawn by MSP430FR5969 alone, the measured current is about 1 micro Ampere, but after I connect CC1120 and put both chips in sleep mode the measured current is 170 micro Ampere.
    I also checked the input current to CC1120 in sleep mode, It draws about 1 micro Ampere.
    I think, I have a problem with MSP430FR5969 because the drawn current raised after I connect it with CC1120.

    Thanks.
  • 0 in reply to Muhsin Atto
    TI__Genius 12315 points

    Hi Muhsin,

    Could you provide your schematic? Except for CC1120 and MSP430FR5969, are there any other components in your board? And what's your measurement device, multimeter or CCS EnergyTrace? 

    B.R

    Winter 

  • 0 in reply to Winter Yu
    Prodigy 60 points
    I use avometer with very good accuracy. It measures the current down to nano Ampere.
    Regarding the schematic, I use these two chips only.

    Thanks
  • 0 in reply to Muhsin Atto
    TI__Genius 12315 points
    Hi Muhsin,

    Please measure the current consumption using LPM3 code example without other operation. You can find this LPM3 code example at below link.
    dev.ti.com/.../


    B.R
    Winter
  • 0 in reply to Winter Yu
    Prodigy 60 points

    Thank you

    I solved the problem. I configured GPIOs of CC1120 wrongly.  I configured  these ports as  tri-state (0XB6) to disable them, but they draw a considerable amount of current in sleep mode. So, I change the setting to forced logic (0X33) , and the power consumption  is reduced to its expected value. 

    Please can you tell me if the receiving current of CC1120 in high performance mode is exactly 22 mA as reported in data sheet or it may be less?

    Thanks in advance for your cooperation.

  • 0 in reply to Muhsin Atto
    TI__Genius 12315 points

    Hi Muhsin,

    The 22 mA is RX Peak Current in High-Performance Mode. It's a typical value in datasheet, which means every single chip has some differences about real measurement values.

    B.R

    Winter