MSPM0C1104: GPIO Read fail by the driver api but the Register shows the value

Yogesh Naik

Part Number: MSPM0C1104
Other Parts Discussed in Thread: SYSCONFIG

Tool/software:

Hello, I am trying to read from a GPIO pin (PA16) on the MSPM0C1104 using SysConfig-generated drivers. I am using the polling method to read the pin state.

-The DIN31_0 register correctly reflects the pin state when the pushbutton is pressed and released.
-However, the DL_GPIO_readPins() API always returns 0x00000000, regardless of the actual pin state.
-I also tried directly accessing the register using its address, but it still does not work.

In the first picture the button is not pressed and the DIN31_0 is holding 1 in 16 th pin (Dont know exactly why it is set) but the api ReadPin is returning 0. In the second picture the button is pressed and there is a change in the state of the pin and the readpin api is still returning 0.

I am attaching the project zip file(gpio_Read) for reference. Any insights on this issue would be helpful!

gpio_Read.zip

7 months ago

0 Bruce McKenney 7 months ago

Guru 99605 points

As extracted from your .zip, the .syscfg for PA16 didn't turn on the internal pullup resistor, so PA16 was floating (when S2 wasn't pressed). Since it was floating, I was able to trigger it (not consistently) by touching the PA16 pin on the Booster Pack header. When I wasn't touching the pin (or S2), the LED flickered randomly, perhaps sometimes faster than I could see.

When I enabled the internal pullup in sysconfig, I got very consistent results.

I suspect what you observed in the debugger was an illusion, where the (floating) pin changed state between the breakpoint trigger and the time the debugger read the registers.

0 Yogesh Naik 7 months ago in reply to Bruce McKenney

Prodigy 120 points

I have also enabled the pull up resistor and have tried. I get the same result. If possible can you attach the zip file of your project so that I can verify the same

0 Bruce McKenney 7 months ago in reply to Yogesh Naik

Guru 99605 points

Which project are you interested in?

My procedure: (a) imported directly from the .zip (b) noted the behavior (c) set the pullup (first in Registers, then in sysconfig) and noted the behavior (d) re-imported directly from the .zip (e) repeated step (b). Step (d) was to make sure I didn't stick my elbow into something else.

I've attached before/after copies of the .syscfg. "diff -w" indicates that the only difference is the PULL_UP line.

I used CCS v12.6.0 (Sysconfig 1.21.0). I suppose it's possible there's a difference between the versions, but -- due respect -- it's easier to suspect something procedural.

/cfs-file/__key/communityserver-discussions-components-files/908/gpio_5F00_software_5F00_poll_2D00_orig.syscfg.txt

/cfs-file/__key/communityserver-discussions-components-files/908/gpio_5F00_software_5F00_poll_2D00_pu.syscfg.txt

0 Yogesh Naik 7 months ago in reply to Bruce McKenney

Prodigy 120 points

Hello Bruce, I have used your /cfs-file/__key/communityserver-discussions-components-files/908/gpio_5F00_software_5F00_poll_2D00_pu.syscfg.txt, and yet I get the same results. My api is always returning zero. What might be the issue here? Is it the ide problem? I am using the 12.8.1 version

0 Bruce McKenney 7 months ago in reply to Yogesh Naik

Guru 99605 points

I imported your project into CCS 12.8.1 and I see the same behavior I reported above:

1) Without the pullup, I sometimes see readPins return 1 for PA16. (This is not unexpected for a floating pin.)

2) With the pullup, I always see 1 for PA16.

3) When I press S2 I always see 0 for PA16.

Can you describe your exact test sequence? We evidently are doing things differently.

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MSPM0C1104: GPIO Read fail by the driver api but the Register shows the value