This project was actually completed and there is an "official" 8052.com SBC that has been designed, built (PCB), and tested. It's actually already on the site here but in a password-protected directory because I want to look over it one more time before I make it public. That'll probably happen within two weeks.

The SBC supports Atmel 89S8252 ISP (hardware-compatible and tested with the new 89S8253), Dallas 89C420 ISP (and other similar Dallas MCUs), has a memory-mapped 4x4 keypad, two connections for a 44780 LCD so the LCD can be driven in either memory-mapped or direct-connect mode, an Atmel AT25010A serial EEPROM (SPI), a Dallas DS1307 real-time clock (I2C), a LED, selectable reset circuit using either a RC network (yeah I know) or a supervisor IC, has an EPROM socket (generally useless, but it's there), and an SRAM socket allowing up to 32k in external RAM that can also be seen as code memory facilitating loading of code via a monitor program. Pretty much the entire bus is exposed via a bunch of 2x8 headers.

What is "official" about it? Only that I plan on expanding the tutorials to cover additional topics. Rather than making abstract examples that don't work on any particular hardware, the "official" SBC provides a basis on which the code examples will be known to work.

Why use an SBC rather than a SiLabs evaluation board? The only reason I really can think of is if part of the exercise is to learn and understand external components and how they interact with the microcontroller. If you already understand that then I'm not sure there's any advantage to using an SBC, really.

And I agree that a "universal" SBC is pretty much impossible. The best you can do is expose the entire bus and make it easy to connect to other things. The SBC won't be able to do everything, but via easy connections it will be able to be expanded to do just about anything.

Regards,
Craig Steiner