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Using the MiSPI3 on TMS570LS1115

Miguel Amezcua Peregrina
Genius 4015 points
Other Parts Discussed in Thread: ADS1271, HALCOGEN

Hi

I'm doing a school project with this MCU.

I need 12 PWM outputs 

24 inputs for encoders, using the N2HET Module 

1 SPI for the ADC of the signal.

I was wondering about SPI... Checking the datasheet of the MCU, I saw that there is a SPI4, a MiSPI3 and the MiSPI5 and the MiSPI1. I'm using the ADS1271 and my question is... which pins could I use, that doesnt interfere with the ePWM module or the pins 23, 24, 28, 106, 118, 6, 124, 39, 125, 41, 139, 40, 15, 96, 91, 37, 92, 4, 107, 3, 127, 54 and 9 from N2HET module and one from the ECAP module to be able to have the 24 encoder interruptions and one SPI working for the communication of the ADS?? Because I saw that the MiSPI have many pins but Im not sure if I really need all.... 

could I only use the MiBSPI3CLK, MiBSPI3NCS[0], MiBSPI3SIMO[0], and the MiBSPI3SOMI[0] and the pin 97  (ECAP) instead of the one from N2HET that is related to the MiSPI3 (pin 96)?

Do I really need the MiBSPI3NENA?

If im using the ADS1271 which pins do i rally need for SPI??

best regards 

  • 0
    TI__Guru 68920 points

    Hi Miguel,

    When you use the MibSPI, you only need to select the CLK, SIMO[0], and SOMI[0] to create SPI transfers. Chip selects and the other data pins (if available, if not available then SOMI[0] and SIMO[0] are simply called SOMI, SIMO) are not needed.

    The ENA pin is useful as a hardware handshake when you want 2 TMS570 chips to talk to each other over SPI. It can speed up the average communication rate significantly. But you don't need it for the A/D converter.

    You'll need to work through the pin muxing to figure out if you can get all your functions simultaneously. But with HET and ePWM you should be able to pick the pins individually from the pinmux** rather than in groups.


    EDIT:  There is a 'PINMUX' tab in HalCoGen that will help you allocate the pins of the device... 

  • 0 in reply to Anthony F. Seely
    Prodigy 70 points
    ok. thanks!! one more question...

    the crystal of the MCU, the one of 16Mhz, is enough for the MCU to work with the ADS1271 right??