Talk:MSP430 LaunchPad Drive LED

Comments on MSP430 LaunchPad Drive LED -

Ek78 said ...
Why there are arrows TO (not from) led at picture?

--Ek78 04:20, 28 January 2011 (CST)

Decimus said ...
Is male header or female header is necessary?Or can we directly solder it.If its necessary how we solder it

--Decimus 05:46, 11 April 2011 (CDT)

Dsferrer said ...
help, trying this on my msp-exp430g2. after successful debugs, download, resetting, plugging and unplugging the experimenters board it doesn't work.. i notice touching only the pin 1.3 with my fingers turns on the LED but using the switch (s2) doesn't do anything. i am using USB power btw.

--Dsferrer 04:10, 11 October 2012 (CDT)

Disaster said ...
I've got same problem as Dsferrer. Is anyone tell me how to solve it ?

--Disaster 15:53, 12 December 2012 (CST)

DhaneshM said ...
I am also facing the same problem. after following this sample program. seems it interrupt is generated only when the P1.3 goes High..please help!..

--DhaneshM 13:16, 23 December 2012 (CST)

Perci said ...
Using de LaunchPad is necessary to add the folowing instructions: P1REN |= BUTTON; //Enable the pullup resistor P1IES = BUTTON; //Interruption is set with a high-to-low transition

--Perci 12:14, 2 January 2013 (CST)

Eckert86 said ...
Shouldn't it be Ic=Ib*beta INSTEAD OF Ib=Ic*beta?

--Eckert86 09:48, 25 January 2013 (CST)

Nicknml said ...
It is also possible to directly drive an LED from a digital I/O pin like you can with an Arduino or is it simply the case that the I/O pins don't provide enough current? Can a 2N2222 NPN transistor also be used?

--Nicknml 08:46, 19 February 2013 (CST)

Joum said ...
Note that the jumper that must be open isn't J3 but J5. Namely, the P1.0 jumper.

--Joum 12:43, 4 March 2013 (CST)

Steven Smith said ...
I was having the same issue with getting the onboard s2 to trigger the interrupt, and I got erratic behavior when touching the pin.

I wasn't able to resolve it with my Launchpad purchased recently with a MSP430G2553 by simply setting the P1REN to enable (earlier comment). One note is that after you set P1REN, you can set it to pull up (1) or pull down (0) by writing that bit to the appropriate P1OUT register.

The code I added between P1IE and enable interrupt was:

P1REN |= BUTTON; //Enable the pullup/pulldown resistor P1OUT |= BUTTON; //Set P1 Pin 3 to pull UP

As a note, the switch connects P3 to ground, and it is normally open. So if you press it, you drop the pin to 0. If you open it, you should read ~3.5V on the header pin if you probe it with a multimeter. I was getting ~1.5V with just commanding P1REN, but full voltage after setting it to pull up. YMMV.

--Steven Smith 09:07, 30 March 2013 (CDT)

Macsek said ...
I am quite new to MSP430 so I might be wrong, but this part seems to be faulty:

"The maximum total current, IOHmax and IOLmax, for all outputs combined, should not exceed +- 12 mA to hold the maximum drop specified.” This means for each pin we have a maximum output current of 1.5 mA. Also mentioned, that the maximum current for the port is 48 mA."

This is currently page 19 on the referred pdf file. Note 1 is removed, only Note 2 remained there (as Note 1), "(1) The maximum total current, I(OHmax) and I(OLmax), for all outputs combined should not exceed ±48 mA to hold the maximum voltage drop specified."

It means nothing more than the total current should be kept under ±48 mA to keep the specified power drop. Having a maximum of 1.5 mA is just a case when we want to keep the power drop and have a load on all the output pins. (Actually this would be 48mA/10 ports, resulting somewhat less than 5mA).

It is enough to see that maximum 1.5mA/pin is unlikely reading the Test Conditions column in the referred table, where "I(OLmax) = 6 mA (1)" is written.

--Macsek 07:18, 5 April 2013 (CDT)