I have done something like this a few years ago.
I had a PIC running a small program written in assembler, the program read the ADC and wrote the digitised value to the UART every second or so.
The UART sent the data as 9600bps asynchronous data to an RS 232 serial interface.
In a laptop PC I had MS Excel (2003 !) which had an "add-in" called PLX-DAQ.
The PLX DAQ intercepted the data which appeared on a serial port and wrote it into a cell in the spreadsheet.
All in all it worked quite well.
For PLX-DAQ, look here:
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JimB