Connect Launchpad GPIO port

Daniel Adarme

hello,

so im trying to configure the Tiva C Connect launchpad to send an output signal to open a lock. I am trying to configure port PC6, which is GPIO Pin 5 from the datasheet. I am using the function

GPIOPinTypeGPIOOutput(GPIO_PORTC_BASE, GPIO_PIN_5);

It build and runs with the rest of my code, however, when I connect to the multimeter, I still do not have a high voltage.

Please advise.

Regards,

Dan

over 9 years ago

0 Amit Ashara over 9 years ago

TI__Guru**** 244400 points

Hello Daniel

PC6 requires GPIO_PIN_6 as the argument

Regards
Amit

0 Daniel Adarme over 9 years ago in reply to Amit Ashara

Intellectual 590 points

Hey Amit.

so I made the attempt again and still im achieving a 3.4mV reading from the DMM.

here is my code block, is there anything wrong with it?

void
outputSolenoid(void){
GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, GPIO_PIN_0); //to turn on the led so I know the function was called
GPIOPinTypeGPIOOutput(GPIO_PORTC_BASE, GPIO_PIN_6);
GPIOPinWrite(GPIO_PORTC_BASE, GPIO_PIN_6, GPIO_PIN_6);
SysCtlDelay(800000000);
GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_6, 0x0);
GPIOPinWrite(GPIO_PORTN_BASE, GPIO_PIN_0, 0x0);
SysCtlDelay(25000000);
}

0 Amit Ashara over 9 years ago in reply to Daniel Adarme

TI__Guru**** 244400 points

Hello Daniel

Did you check the schematic to see if there are any wire shorts on the launchpad that maybe creating a short on the board and thereby causing a lowv voltage reading

Regards
Amit

0 Daniel Adarme over 9 years ago in reply to Amit Ashara

Intellectual 590 points

I don't think there is any wire short, but were my codes correct?

0 Daniel Adarme over 9 years ago in reply to Daniel Adarme

Intellectual 590 points

there is nothing connected to boosterpack 1 on the board. there is the kentec lcd connected to boosterpack 2

0 Amit Ashara over 9 years ago in reply to Amit Ashara

TI__Guru**** 244400 points

Hello Daniel

Is the clock to GPIO port C enabled. Did you check via the debugger that the GPIO registers are correctly configured

Regards
Amit

0 Daniel Adarme over 9 years ago in reply to Amit Ashara

Intellectual 590 points

would that be utilizing the GPIOPinConfigure() ??

0 Amit Ashara over 9 years ago in reply to Daniel Adarme

TI__Guru**** 244400 points

Hello Daniel

That would be call to the SysCtlPeripheralEnable with the correct argument as given in the documentation

Regards
Amit

0 Daniel Adarme over 9 years ago in reply to Amit Ashara

Intellectual 590 points

is this what you mean?

ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);

0 Daniel Adarme over 9 years ago in reply to Daniel Adarme

Intellectual 590 points

Amit, you're the man. thanks

0 Amit Ashara over 9 years ago in reply to Daniel Adarme

TI__Guru**** 244400 points

Hello Daniel

Yes. Either flash or ROM call will do

Regards
Amit

0 cb1_mobile over 9 years ago in reply to Daniel Adarme

Guru 117855 points

Daniel Adarme said:
outputSolenoid(void){

Might that solenoid's coil "over-challenge" poor PC_6? To what voltage is the (other) side of the solenoid's coil connected? (that had better be 3V3 or (maybe) 5V at maximum)

Have you noted the solenoid's coil voltage & current - and insured that (both) fit w/in the MCU's output capability?

Usually - but not always - it is wise to "buffer" the feeble MCU pin via a FET or other device - and not subject it to the "oft hostile, outside world!"

While Amit is indeed "the man" the lack of Port_C's enabling conflicts w/poster's statement, "It build and runs with the rest of my code" - does it not? Most always (perhaps always) when we fail to enable a GPIO Port - (and then make such call) a strong error is produced which prevents, "build & run!"

What to do - to troubleshoot further:

temporarily remove any/all connections to that solenoid - and repeat your voltage probe of PC_6.
suggest that you measure from PC_6 to ground - note & report that resistance
if SysCtlDelay employs the SysTickTimer() (I can't recall - we use mostly 180MHz MCUs) will 800 million "fit" w/in the 24 bit SysTick? Note that too brief a pulse is unlikely to be "felt" by your solenoid's coil.
it is normal/customary to employ a protection diode between your switched side of the solenoid's coil and the coil's energizing voltage. (this to clamp the voltage transient when you "release" the solenoid.)
And how sure are you that you are (really) probing & reading PC_6? And that nothing else attaches to that pin?
You repetitively call GPIOPinType() - it is only required once - should be "outside" outputSolenoid()...

0 Daniel Adarme over 9 years ago in reply to cb1_mobile

Intellectual 590 points

You are indeed correct sir, and we are driving a MOSFET with the output of the MCU, we just needed the output of the MCU turned on.

We were only testing the output pin on the launchpad to ensure we were achieving an output. (referenced to ground)

We already have the solenoid circuit designed and tested with an input voltage of 2.4 to 3.3V.

0 cb1_mobile over 9 years ago in reply to Daniel Adarme

Guru 117855 points

Good that - yet it remains unclear as to whether you've NOW achieved near 3V3 from PC_6! Our findings are that ALWAYS - when a call is made to an MCU Port which has NOT been enabled - the Fault Handler is our destination!

And your first post claimed that you "built and ran" - which flies in the face of "Failure to enable the GPIO Port."

So - would you be so good as to clarify - have you output from PC_6 now?

0 Daniel Adarme over 9 years ago in reply to cb1_mobile

Intellectual 590 points

Yes we did. 3.295 V to be exact! Thank you for your support.

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Connect Launchpad GPIO port