my question is to establish a connection between sensors and MSP430 with the ADC pins. Then taking those data to store it in SD card. SD card is in SPI mode. I want to graph these data on Excel or something. What functions should you recommend for easily making graph out of the data? (The program code is in "C") I am a beginner in these subjects, so would you please tell in simplest ways. Thank you!
If what you are asking for is a easy way to write data (using c) and then read/graph it using excel then I would recomend that you simply write to a csv file that you import into excel.
See, for instance, this link for a simple example of that.
Based on the fact that you're a beginner, my recommendation is that you for now stop working on this project. This is not a project for a beginner.
What I would instead recommend is to make several smaller projects which when combined together will provide equivalent results as the big project. When you complete the smaller projects, start working on integrating them into a bigger project.
So some ideas about the little projects:
First learn how to blink an LED. After that learn how to send and receive data using serial port on the MSP430 and learn how to communicate with the PC using the serial port. The MSP430 Launchpad for example has all needed electronics to enable serial communication using USB and to allow programming and debugging. Have the MSP430 send back the sentence you sent it or have it work as a simple calculator. Send it 2 + 2 and have it output 4. Here you can find analyses of the demo program for MSP430 launchpad and it explains how serial communication works.
After that learn how to use the ADC and how to send raw ADC data to the PC using serial port. Some serial terminal software such as Realterm can record the received data, so with some formatting you may already have data ready for processing in Excel. Here for example is a project which uses ADC to read values and send them using serial port. Other tutorials on that site should be useful too. Here is another example of reading data from ADC and sending it over serial port.
Next learn how to interface with an SD card and how to store and read data on it and how to read raw bytes. After that, you need to learn how to work with filesystem if you want the data to be readable by some other computer. This application note explains how to work with MSP430 and SD cards. Read it and try the examples.
Once you have learned all those things, you can try to integrate them into a single project.