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DSRnathan
Level 3
Level 3
50 sign-ins 25 replies posted 25 sign-ins
Hello Everyone,
I am using Triboard TC277. I found the status of of some port Pins are "High" by default in "Port Pin Input mode-(eg:- P00_IN)" status. Those pins are not resetting to zero or low. How to change those Port Pin status after a Reset or PORST is invoked, i.e all Pin status of the Ports to go "Low" .

Please have a look at the attached screen shot for example as I shaded some Pins(Input mode of the Port) which always stay High regardless of reset activity in Triboard.
Kindly Help me in this regard.

Many Thanks in advance,

Kind Regards,
Deepak4403.attach
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3 Replies
MoD
Employee
Employee
10 likes given 50 likes received 500 replies posted
There are only two possibilities after reset, internal pull-up device active or pin in tristate. If you need a low on the pins then you must configure the pins as input with pull.down device active via software after reset.
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DSRnathan
Level 3
Level 3
50 sign-ins 25 replies posted 25 sign-ins
Hello MoD , Thank you veryh much for the reply. i am trying to change the input pin state to pull down using "SetinputMode". Please can you mention which register is responsible for the PORST to indicate the pins should go low after reset invoked.
Many thanks inadvance.
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NeMa_4793301
Level 6
Level 6
10 likes received 10 solutions authored 5 solutions authored
Output low is not an option for PORST.

HWCFG[6] controls whether the internal pull-ups are activated for all GPIO, or if all GPIO are high impedance inputs.

On your TC277 TriBoard, HWCFG[6] is brought out to the DIP switches: see Figure 4-1 HW Configuration TC277A/TC2D7 DIP-Switch in the TriBoard manual. If switch 4 is OFF, the internal pull-ups will be active. If switch 4 is ON, the inputs will be floating.

Your application can then configure the pins as inputs or outputs with the port registers (PDR, Pn_IOCR, etc.)
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