MSP430F6726: Inquiry about GPIO Input-configuration.

Takayuki Miyazaki

Part Number: MSP430F6726

Hi team,

Our customer is developing their system with MSP430F6726. Customer configured P1.1/P6.7 as Input terminal ((pullup/pulldown is disabled). When 3.3V is supplied to those pins, it seems to show 2V. Therefore, customer would like to know the reason why this behavior occurs. I tried to summarize their report and attached it(MSP430F6726_issue.pdf). Can we have your Expert's advice/comments on this, please?

If this should be expected behavior, could you elaborate Input impedance, please?

Just in case, I'm asking customer MSP430's power supply voltage.

Best regards,

Miyazaki

over 3 years ago

0 Keith Barkley over 3 years ago

Guru 35680 points

Knowing the supply voltage is key. If it is at 1.8 V, applying 3.3 V could cause the ESD diode to kick in. The max for any pin is usually 0.5V above Vdd.

0 James Evans over 3 years ago

TI__Mastermind 49692 points

Keith's right here. Let us know what the supply voltage is. They can find the absolute maximum input voltages with respect to the supply voltage in the datasheet. Also, how are they measuring the voltage at the input? With a scope or multimeter? If those pins are set up as digital I/O's, they aren't going to measure the input voltage like an ADC input and will depend on the VIL and VIH levels which also depends on the supply voltage.

Let us know.

Regards,

James

0 Takayuki Miyazaki over 3 years ago in reply to James Evans

TI__Genius 10120 points

Hi Keith, James,

Thank you for your comments. Customer noticed wrong oscilloscope-setting. I closed this ticket.

Best regards,

Miyazaki

0 James Evans over 3 years ago in reply to Takayuki Miyazaki

TI__Mastermind 49692 points

Miyazaki-san,

Thank you for sharing the solution and for marking the thread "Resolved".

Regards,

James

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MSP430F6726: Inquiry about GPIO Input-configuration.