AnsweredAssumed Answered

TWR-K53N512's SPI Lines Under Votage when transmitting

Question asked by Paul Santos on Aug 14, 2016
Latest reply on Aug 27, 2016 by EARL GOODRICH

Hello All,

 

I have found when I am using the TWR-K53N512's SPI2 module, the clock and data output lines are under voltage when transmitting. I've measured during idle and both lines are found to be ~3.3V. However, during a transmission I find that I measure ~1.6-1.8V for a High. My slave device can only register a high as a min of 2.0V. I currently have the following set for the Port settings.

 

  PORT_SetPinMux(PORTD, PIN12_IDX, kPORT_MuxAlt2);           /* PORTD12 (pin 141) is configured as SPI2_SCK */

  PORTD->PCR[12] = ((PORTD->PCR[12] &

    (~(PORT_PCR_PS_MASK | PORT_PCR_DSE_MASK | PORT_PCR_ISF_MASK | PORT_PCR_PE_MASK))) /* Mask bits to zero which are setting */

      | PORT_PCR_PS(PCR_PS_UP)  /* Pull Select: Internal pullup resistor is enabled on the corresponding pin, if the corresponding Port Pull Enable Register field is set. */

   | PORT_PCR_PE(1)

   | PORT_PCR_DSE(PCR_DSE_HIGH) /* Drive Strength Enable: High drive strength is configured on the corresponding pin, if pin is configured as a digital output. */

    );

  PORT_SetPinMux(PORTD, PIN13_IDX, kPORT_MuxAlt2);           /* PORTD13 (pin 142) is configured as SPI2_SOUT */

  PORTD->PCR[13] = ((PORTD->PCR[13] &

    (~(PORT_PCR_PS_MASK | PORT_PCR_DSE_MASK | PORT_PCR_ISF_MASK | PORT_PCR_PE_MASK))) /* Mask bits to zero which are setting */

      | PORT_PCR_PS(PCR_PS_UP)    /* Pull Select: Internal pullup resistor is enabled on the corresponding pin, if the corresponding Port Pull Enable Register field is set. */

   | PORT_PCR_PE(1)

   | PORT_PCR_DSE(PCR_DSE_HIGH)    /* Drive Strength Enable: High drive strength is configured on the corresponding pin, if pin is configured as a digital output. */

    );

 

Can anyone help me figure out why this is?

 

Thanks!

Outcomes