Using the TI LaunchPad from your KoP

[ILAMtitan]

Originally Posted by philso

I am contemplating using the TI MSP430 Launchpad for a project I have in mind. I would like to use this as an opportunity to learn to use TI microcontrollers. Please advise if the following is workable.

I would like to build a device to control the DC current to a load using a PWM output stage and monitor the load current and voltage using two of the ADC inputs. I would want to store the time-stamped data, most likely on an SD Card. The time-stamp does not have to be the actual time. The time since the start of the sequence would be sufficient. I was considering using a touch screen LCD for the user interface. I found the following Booster Packs on the 43oh web site. I am comfortable designing the switching circuitry myself since that is what I do for my day job.

http://forum.43oh.com/topic/1700-sdcard-booster-pack/

http://forum.43oh.com/topic/6149-24-...t-touch-panel/

Philso,
The Launchpad would be a perfect platform for what you're trying to do. The only issue you might run into using the booster packs you've found that I see is that they will both probably use the same SPI port. You would have to double check the pin-outs to ensure that the chip select lines are on different pins so you can mux them properly. I've worked with RobG and BlueHash from 43oh before though, and they are both great resources.

It looks like RobG made a booster pack that integrates the SD and LCD into a single design: https://www.tindie.com/products/RobG...d-card-socket/
You might want to take a look at that one to see if it will meet your requirements.

Another consideration to make is how accurate you need your current measurements. The Launchpad that we put in the KoP is the MSP430F5529, which has 12 bit SAR converters. We just recently launched the MSP432P401 LP which has 14bit converters that might give you some additional dynamic range/accuracy if needed. In addition, that board has the new MSP432 processor, which is a 48MHz 32bit Cortex M4F. The additional clock speed should also give you higher resolution PWMs (but I haven't looked into this specific feature).

Both of the Launchpads listed will also include an internal RTC capable of making accurate time stamps for your data logger. You can either set it to the current data/time, or just use it in free run mode as you described. I'm not personally familiar with designing and operating a DC current source via PWM, but I can ask around the 430 team to see if anyone has information I can share if that would help.