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AWR2243BOOST: Questions about nReset

Tim Teuber
Intellectual 390 points
Part Number: AWR2243BOOST
Other Parts Discussed in Thread: AWR2243, AWR2944

Hello Team,

i am currently trying to interface the AWR2243Boost via I2C with an external host MCU (Nvidia Jetson Nano). First i tried to detect connected i2c-devices on the jetson, but the device adress 0x28 was only ever found when i pressed nReset shortly after starting to scan for devices. Then i tried to send the CNYS message but that did not really worked out. I think i am facing an issue with the right timing of the nReset triggering. Could you provide me with information about the correct Schedule? Whats the relationship between nReset and Warm Reset. Does nReset affect the HostIRQ Signal?

Regards

Tim

  • 0
    TI__Guru* 91206 points

    Dear Tim - 

    Thanks for the post and welcome to E2E!

    Referencing the datasheet (https://www.ti.com/lit/ds/symlink/awr2243.pdf) for the device -nReset is an input and Warm_Reset is an output. 

    The relationships you need to respect here are shown graphically on page 23.

    From the schematics of the EVM, https://www.ti.com/lit/zip/sprr415 sheet 11 of Rev B schematic has the BoosterPack headers, specifically you can use pins on J6. 

  • 0 in reply to Josh Wyatt
    Intellectual 390 points

    Hello Josh,

    Thanks for the quick and informative response.

    So for proper functionality of the AWR2243 I need to ensure that the nReset is pulled low by the host MCU until PGOOD indicates a stable DC power?

    Is the nReset involved in the functionality of the I2C interface and does it have to be pulled low aside from the wake up process?

  • 0 in reply to Tim Teuber
    TI__Guru* 91206 points

    Dear Tim -

    Correct - the AWR294x device expects all external 1.2V, 1.8V and 3.3V voltage rails as well as all SOP[4:0] lines to be stable before NRESET is deasserted for a successful device bootup. IO state is not guaranteed until the VIOIN and VIOIN_18 supplies are available. The part is not ready to be used until device boots up and I2C of course would not be available until complete either.  You should have pull-up resistors on the I2C lines. 

    Also, there is a table in the Technical Reference Manual for the AWR2944 https://www.ti.com/lit/ug/spruiv5c/spruiv5c.pdf , starts page 3111 which has overview of reset types and sources, with descriptions, and is followed by Reset Domain descriptions table, which should be informative/helpful to you.