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CC3220: several question's for the "CC3220, CC3120" wifi chips

Shai Berman
Mastermind 7400 points

Part Number: CC3220

Hi team,

can you please advise the questions below:

First to clarify the about our system needs.
• Our system is very low power unit (operating from a battery).
• Today we are using Nanotron chips (propriety protocol).
• We can accept large current for several hundred mili-sec (but most of the day several micro ampers).
• Our system is without any connector or button (it is completely potted).
• The only way to connect to it is via the wifi.
• The wifi chip is used for very small data transfers (several bytes).
• We checking the option to replace the Nanotron chip with TI wifi chips.

We are planning to embed the TI wifi chip in 2 stages:
• The first stage is a quick one, so we will use the CC3220 & connect it to our CPU via the application processor AT command.
• The second stage (for better power & price), our low power CPU will connect to the CC3120 (API).

For knowing if both options above are applicability, we will appreciate some more data about the following issues:

1. When using the CC3220 in idle connect power mode, does the application processor (with the AT command) can be in a low power mode?

  • And if so what is the expected current?

2. For calculating the power budget of our battery we need to know:

  • Expected time in TX power mode for transferring few bytes message?
  • Expected time in RX power mode for receiving few bytes message?
  • If we are in hibernate mode & getting command to transmit a short message (via the wifi) and are waiting to reply.

2. how is the best way to work from minimum power point a view:

  • Stay in idle connect mode until we get the answer?
  • Returning to hibernate mode after the tx end, and check for an answer every second or so?
  • Please answer the above question for both the CC3220 & CC3120.
  • Every timing that you know about the wifi connection with the appropriate current (power mode), so we can calculate our power budget correct.

3. In our assembly line, we can program the wifi chip for a default connection,

  • But after it, the product is totally potted And sent to the field.

                      i.      How do you suggest that we change the connection parameters to the real router in the field?

                      ii.      Using our product as an access point for the above will consume a huge power or am I wrong?

Thanks a lot and kind regards,

Shai

  • 0
    TI__Mastermind 38275 points

    Hi Shai,

    I will work on providing a better, and more thorough, response on Monday. For the time being please see the initial feedback below:

    Many of your power related questions can be answered in the Power Management Application Report ( http://www.ti.com/lit/swra502 ). such as typical Idle Connected (or Always-Connected) current consumption, typical TX/RX burst current consumption, some example test/use cases with graphical representation, and overviews of the different networking subsystem and MCU power modes.

    For #3:

    i. Are you wondering how you would re-provision the device to a new AP, or wondering how you would update the firmware?

    ii. Using the device as an AP, rather than a station, will definitely increase current consumption.

    Best,
    Kevin

  • 0 in reply to Kevin Allen18
    TI__Mastermind 38275 points
    Hi Shai,

    Here are some more thorough answers to your questions:

    1. The Idle Connected (or Always-Connected) use case involves the CC3220 being in LPDS and waking up to check beacons from the AP. The sleep interval can be lengthened by setting the Long Sleep Interval (LSI). I believe the application processor would have to wake up and be in active mode when AT commands are received.

    See sections 1.8.9 and 1.10.2 within http://www.ti.com/lit/swra502.

    2. This will depend on how you handle transmitting and receiving packets, the bit rate, and the AP being used.

    See section 1.8.13 and Table 6 of the the same doc.

    3. This will really depend on the application. I.E. if you need to always be connected to an AP or not and how long the interval between packets of information will be.

    The Power Management Application Report goes over some of this and this wiki explains a lot as well: processors.wiki.ti.com/.../CC3200_Power_Management_Optimizations_and_Measurements

    4. There are a number of provisioning methods that you can pick from to add a WiFi profile (SSID/password) to the device. Is power consumption a big concern for your application when it comes to provisioning the device?

    See processors.wiki.ti.com/.../CC3120_&_CC3220_Provisioning

    Let me know if you have any additional questions on this

    Best,
    Kevin
  • 0 in reply to Kevin Allen18
    Mastermind 7400 points
    Kevin,
    Thank you very much for the detailed answer, I'll keep you posted.

    Best,
    Shai