Actions
Forum Thread Details
  • Replies 39 replies
  • Subscribers 8 subscribers
  • Views 442 views
  • Users 0 members are here
Related

Have a question for TI re: The Internet of the Backyard Challenge? Ask here!

doctorcdf

This thread is dedicated to questions for the Internet of the Backyard challenge; Texas Instruments' staff will be monitoring it regularly.

 

Thanks!

Parents

  • I wish to get some clarification on the use of a 5V power supply with the CC3200 Launchpad. What had grabbed my attention was a previous blog post by Alexander Rowsell "Eternal Power: Keeping the CC3200 Juiced".

     

    Here the video was showing the launchpad powered through J19. I am only just starting to get my head round all the documentation but nothing obvious came up in the MCU launchpad hardware user guide. In the guide (section 2.5) it only refers to the device being powered by USB or by 2xAA/AAA batteries. Other than J19 there is also P31 pin shown as 5V. If you power through either of these connectors do I need to do anything with J12 / J13 jumpers as those are related to USB power source.

     

    Are there any technical details / description of constraints on this use of these connectors to power the launchpad.

     

    Thanks and look forward to receiving some answers.

Reply

  • I wish to get some clarification on the use of a 5V power supply with the CC3200 Launchpad. What had grabbed my attention was a previous blog post by Alexander Rowsell "Eternal Power: Keeping the CC3200 Juiced".

     

    Here the video was showing the launchpad powered through J19. I am only just starting to get my head round all the documentation but nothing obvious came up in the MCU launchpad hardware user guide. In the guide (section 2.5) it only refers to the device being powered by USB or by 2xAA/AAA batteries. Other than J19 there is also P31 pin shown as 5V. If you power through either of these connectors do I need to do anything with J12 / J13 jumpers as those are related to USB power source.

     

    Are there any technical details / description of constraints on this use of these connectors to power the launchpad.

     

    Thanks and look forward to receiving some answers.

Children
  • in reply to BigG

    BigG,

    you can get the schematics for the CC3200 Launchpad at this link to analyze the power circuitry:

    SimpleLink Wi-Fi CC3200 LaunchPad Reference Design - CC3200-LAUNCHXL-RD - TI Tool Folder

     

    Anyway, if you look into the schematics of Launchpad Rev3p2, If the USB power is not available (VBUS_USB1 is N/A), J19/P3.1/VCC_MCU_5V can also be used as the power input of the U3 TPS79601 LDO which outputs the 3.3V supply for the CC3200. The J13 and J12 (or R62) jumper shall be kept connected to supply the CC3200.

  • in reply to Former Member

    Hi Leo, thanks I will take a look.

     

    Another small thing. What is the logic behind the pin numbering. I, without much thought, referred to 5V pin as being row 1 under P3 and therefore is P31. However reading in the document under section 2.4.8 Pin Connector Assignment and on the board itself each pin is referenced differently. Hence for example the pin aligned to row 2 under P1 is referred to as P58. Is there some other linkage to this reference numbering ([update[ just to clarify this is linked to SDK definitions). Just curious.

  • in reply to BigG

    BigG,

     

    I agree the GPIO numbering is somehow confusing, I personally have mentioned it before to the product group team. Anyway, the P1-P4 connecters of the CC3200 Launchpad can be address as P1.x-P4.x, and this is derived from the Launchpad ecosystem boosterpack standard:

    http://processors.wiki.ti.com/index.php/BYOB#Electrical_and_Physical_Specifications

     

    In your specific case of P1.2 (CC3200 P1 connector, row 2), it is basically connected to pin number 58 of the CC3200 which is GPIO_03. You can just check this in the schematic or the device datasheet as follows: http://www.ti.com/lit/ds/symlink/cc3200.pdf - chapter 3 "Terminal Configurations and Functions".

  • in reply to Former Member

    Hi Leo

     

    Been looking at TPS79601 spec sheet. I see the constraints I was looking for is that it is a 1 amp linear voltage regulator, accepting voltage input range of 2.7V to 5.5V. Just a suggestion, but maybe it would help others if this info is included in the main hardware reference document as the TPS79601 datasheet does not come up in the TI website search results if you do a search for CC3200 launchpad LDO.

     

    Then just trying to establish my own platform of understanding by throwing in a few "what if's"... so what happens if you are powering the launchpad through J20 with your 2xAA's and then absent-mindedly plug in your USB cable but forget to short connectors as required. That is, how does the launchpad handle the unlikely scenario of both battery power input and 5V connected through LDO.

  • in reply to BigG

    It looks like the is a FET switch configured to protect against reverse voltage and should also protect the batteries from harm if the USB or other supply is also connected (Q2 bottom right)