mnpumar

I'm thinking of doing this with charlieplexing instead of 5 microcontrollers. I came up with a design that uses only 15 pins, but unfortunately it seems that the msp430g's are limited to 10. Are there any msp430s with more than 10 IO pins that are also DIP?

Thanks cde and GeekDoc! Just to clear things up here now, I CAN in fact connect any voltage I want for vcc and still switch the transistor on and off with the output of the MSP430, correct?

Ok, now I'm super confused. You're saying that Vcc must be the same as the output of the pin that the transistor is connected to? Why then in this schematic do they have a 2.15 KOhm resistor connected between the output pin and the transistor? http://processors.wiki.ti.com/index.php/MSP430_LaunchPad_Drive_LED And isn't the voltage at the top of the transistor different than the voltage where P1.0 is connected?

Thanks Guys! So if I understand the schematic correctly, Vcc can be whatever I choose, and the resistor lowers it to the proper level for the LEDs, and the output pin connects to the transistor to open/close the circuit?

Can you please elaborate on how I would use transistors to accomplish this? I am looking to turn on/off anywhere from 1-3 of those LEDs per pin on 9 pins. Would bluehash's idea work if i put a diode in front of the pin that didn't let any current into the msp430? I'm guessing the best solution would be to switch to these LEDs: http://www.amazon.com/Joe-Knows-Electronics-Clear-Pack/dp/tech-data/B0040EFF20/ref=de_a_smtd?ie=UTF8&m=A2CKSJGKIJVSBF Assuming the output at each pin is 3V, I would use a 40Ohm resistor for 1 led, 20Ohm resistor for 2 in parallel, and 15 Ohm for 3

Sorry if this is the wrong forum for this question, but it seems the most appropriate. I'm looking to power these LEDs with the output pins of the MSP430: http://www.topbright88.com/50-pcs-blue-led-3mm-13k-mcd_p321.html Since the output is already 3V do I need to add any resistors? If I am using more than at an output do I need to connect them in parallel? Thanks for the help.

u will need five of those, one for each digit and one for the master controller. I ended up buying this today: http://www.amazon.com/9440-JW-350-Jumper-Wire-Kit/dp/B0002H4W0U/ref=sr_1_sc_1?ie=UTF8&qid=1289612101&sr=8-1-spell Think it will all fit?

Thanks for the great ideas, the potentiometer changing the speed sounds like a really fun one to implement! I'm trying to work through the logic of the individual digits in my head right now, and the simplest solution I can come up with to code would be: if(input voltage at pinx != 0){ -increase digit, and depending on its position, determine whether it should be reset to 0 or off. -wait for input voltage at pinx to go back to zero } The way it would work is if a digit is to be increased, the master turns on the pin connected to the digit for a brief

Thanks for the helpful replies! I was really hoping I could set the output to a certain fraction of Vcc so I could showcase my knowledge of ADC's in the other four mcus (since ADC and DAC were covered in the course). I guess this means I am stuck using interrupts for the other four mcus controlling the other digits?

Awesome! I would seriously pay for something like this.

Thanks simpleavr! That is exactly the type of code I was looking for. I have a couple quick questions to help me understand fully how it works: -What makes this method of keeping the time inaccurate? Is it that the processor isn't perfectly calibrated to 1MHz? -Is the mcu asleep while it is waiting for a click to occur? -Will the mcu interrupt whatever it's doing every 50k cycles to increase the clicks counter? What if it's in the middle of processing another function? Will it pause, increment clicks, and then go back to it? If I understand the code correctly, the main loop

The objective is to create something with the knowledge I've gained so far in the course. It is a course on circuit theory, not programming microcontrollers, so I think the original design is more what my professor is looking for. I like your idea for the interrupt trigger, originally I was thinking of using the ADC to send each of the other microcontrollers a certain voltage, and based on that voltage they would determine which number to display. I think I will go with your soultion instead. The document you provided is somewhat what I am looking for. However, I would prefer not to u

Thanks for the reply! I placed my order at DigiKey, their website said they had over 100 in stock, so hopefully I won't have any problems. I also ordered a few more MSP430G2231IN14's to go with it

Hi everyone, I am a student at the University of California at Berkeley, and I came here to do some research for a project. I posted a question about it here: http://www.43oh.com/forum/viewtopic.php?f=8&t=175 if anyone is interested I am a 3rd year Electrical Engineering and Computer Science major ( we have a joint program here). I found out about the MSP430 during a lab section, and I have been intrigued ever since. I ordered a launch-pad on Friday, so hopefully I'll be getting it in the mail sometime soon so I can get started with my project! -Matthew

Thanks for the reply! However, those are a bit more complicated than I was looking for. I am new to microcontrollers, but I have gained some experience using them in a lab for one of my classes. We used the M430F2012, and did some basic things like a blinking LED, an introduction to the ADC, and using a touch sensor. (A copy of the lab is here: http://ucbfeedback.com/assignments/166/pdf if you're interested). Perhaps I should explain my project a little better. I am planning on making a 4-digit digital clock, where each digit is made up of 20 LEDs. Each of the digits will be controll

I am about to start a project with the msp430 launchpad, and my goal is to make a digital clock. I was wondering if anyone knew how to keep track of time inside the microcontroller? For example, when it powers on, it would start at some arbitrary time (like 12:00), and then keep track of the time continuously as it's running. Does anyone know how to do this? Thanks for your help, Matthew