Polling an I/O Pin

What do you have connected to these pins on the device?  Specifically, P3.6 and P3.7?

Also, how do you have the other P3 registers setup?

Hi Moiz,

pls post your initialization code for P3.x pins. It would also be of interest how you check the I/O-pins (how you do the polling) and how you access the other P3 I/O's (P3.0 to P3.5) in your project.

Kind regards
aBUGSworstnightmare 

Hey Guys,

I have two MSP430 on two different boards. Lets call them Unit0 and Unit1. This is how they are connected:

Unit0 -------> Unit1

P1.3 ------> P1.3

P3.6------->P3.6

This is how i setup the ports on Unit0:

P1.3 --- output

P3.6 --- input, resistor enabled, pull down

and Unit1:

P1.3 --- input, resistor enabled, pull down

P3.6 --- output

This is what I am trying to do. When i make P1.3 on Unit0 Hi, it should make P1.3 of Unit1 Hi as well. Which it does. Now, if P1.3 on Unit1 is Hi, I want to make P3.6 of Unit1 Hi, making P3.6 of Unit0 Hi. All this is working for me but the problem arises when I dont want anything to happen on Unit1 when P1.3 becomes Hi. It still make P3.6 Hi.

The only other thing P3.x is connected to is: USCI_A0 TXD/RXD (P3.4/5), becuase I am using the terminal to toggle P1.3 of Unit0 . P3.0-P3.3 are not connected to anything.

I hope I am making sense :).

Thanks for your help

Hi Moiz,

how do you distinguish between the two states for P1.3 (male P3.6 high or not)? 

It looks like you need something like:

if {P1.3 == HIGH)
{ 

if {do something with P3.6 == HIGH)
P3.6 = HIGH; // set to high level

else
// do something else (or not) and keep P3.6 as is 
}

Rgds
aBUGSworstnightmare 

Moiz said:

Hey All,

Im trying to poll P3.6 and P3.7 on MSP4302274. I found out while debugging that for some reason P3IN = 0xF0 when I initialize the hardware. This is messing my project up. I need it to be bit 6 and 7 to be 0 until they are made 1, but for some reason they change. How can I fix this??

Please help!!

I presume you mean MSP430F2274 instead of MSP4302274.

I do not have a MSP430F2274. Prompted by your post, I read the data-sheet. It says that if the ADC10AE0 register BIT7 or BIT6 is set, P3.7 or P3.6 is used as analog I/O respectively. BIT7 or BIT6 of P3IN are meaningless under such circumstance.

Did you see this in the data-sheet? Did you check the setting of ADC10AE10 register?