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Enable Timer-Pins on EVM

abraxas
Prodigy 230 points
Other Parts Discussed in Thread: TPS65950

Hello,

i want to use the A11-A13, A15 pins on the Expansion Connector P7 for frequency-measurement. The EVM manual tells me (page 25), that i have to set T2_GPIO_2 high and GPIO_61 also high, so i get these signals on the expansion connector (because these pins are multiplexed with USB-functions, which i don't need). GPIO_61 is no problem, but T2_GPIO_2 is controlled via the TPS65950, which is connected via I2C to the OMAP.

Do i really have to work on a I2C-solution for communication with the power module, or is there already some kind of tool i can use?

  • 0
    TI__Guru* 86460 points

    It might be easier to do some simple board rework if you have a soldering iron.  Check page 16 of the main board schematic.  You're just looking to pull EXT_nUSB2_EN low.  You might be able to remove R786 to get the right level for T2_GPIO2. 

    If you are working with Linux, you can use the I2C driver already installed and find code that communicates via I2C to the TPS65950 as an example.  If not using Linux, the power optimization code here has example I2C code that talks to the TPS device.

    Regards,

    james

  • 0 in reply to JJD
    Prodigy 230 points

    Thanks for your help!

    Although the EVM manuals says the T2_GPIO2 is per default high, it is not, as i measured. Perhaps this was patched, i don't know.

    Still i could not change the value of GPIO61, it seems to be somehow protected.

    So i changed the  board-omap3evm.c file in the  kernel 2.6.32 source code:


    Line 1145 from

    gpio_set_value(OMAP3_EVM_EHCI_SELECT, 1);

    to

    gpio_set_value(OMAP3_EVM_EHCI_SELECT, 0);

     

    Easy as that. Perhaps this might help anyone :)