Programs for microcontrollers? So tiny programs, by today's standards. Building a program is going to take seconds, no matter what you get.
You didn't say what you have now.
Absolutely any current mainstream CPU will do. Dual core will do, but it's usually so cheap to get a quad core that you might as well. Eight GB of RAM may be enough but, again, the incremental cost of 16 is so low that you might as well do it -- especially if you're going to run some bloated Eclipse based IDE. The work stuff is unlikely to need more than 64 GB of SSD but, again, the incremental cost of 256 GB or 512 GB is very low now.
To be honest, the necessary specs will depend more on what *else* you want to do with the machine.
Computers aren't getting much faster each year now (other than more cores), so if your old one has lasted you 12 years then your new one easily could do that or more, if you buy something with quality hardware. I'm still running a 2011 Core-i7 11" MacBook Air (4 GB RAM) and a 2011 Core-i7 17" MacBook Pro (16 GB RAM, 256 GB SSD, 750 GB hard disk) with no problems other than the battery in the MBP has died and it's non-trivial to get a new one. The higher end Lenovo and Dell things are well built too.
Probably the amount of I/O is more important, though now with USB-C (or Thunderbolt) it's not as important as before because it's got huge bandwidth and you can get any ports you need via port expanders, including legacy stuff that no one would ever build into the actual laptop now -- centronics, SCSI, serial, it's all available with inexpensive USB-C or USB3 adaptors.