Electronic – How to burn hex code program file into AT89S52

I have been using Mon51 with the Cypress FX2 for going on 10 years with very good success. In addition we use the RTXtiny task switcher and code banking. I have found the monitor to be generally solid and with enough functionality for our needs.

To use it we had to "von neumanize" our memory; logically AND PSEN# with RD#, which hasn't been a problem.

We also use the hardware bootloader from serial eeprom which also works tremendously well in my opinion.

This sounds like a job for embedded Linux.

1. Persistent file system. Forget IDE (save yourself 40 pins) and go for a board that uses a flash card.
2. More RAM and Flash. Typical embedded Linux boards have RAM in the megabytes.

As for peripherals, driving 40 servos could be a question here on its own. How are you doing this now? For the rest of your peripheral requirements, here's a board that seems to fit that has a good community as well:

http://beagleboard.org/static/beaglebone/latest/Docs/Hardware/BONE_SRM.pdf

The tool chain has a C++ compiler, it has SPI, UARTs, and even a PWM. This is what's being claimed in the PDF at least, you'll have to make sure that there are drivers for all those peripherals available to you at the application level for whichever distro of Linux that you put on. Hopefully the one they provide has everything you need.

So basically, if you can port whatever you've written to a Linux PC, there's a good chance you can port it to an embedded linux target. However, I'm willing to bet that if all you're using from C++ is <fstream> and <string>, you could probably do a C re-write and save yourself the overhead of Linux.