As Andy says that the main advantage is the 8051's ubiquity. Given as task, there is a number of micros from various manufacturers that are probably much the same price, have the same features so which one do you choose? It comes down to what one you have experience with and what tools you have on hand. Quality 'c' compilers and debuggers cost a few dollars so you really don't want to keep on re-investing each time you use a new micro. Apart from this, I don't think there is anything particularly compelling about the 8051 - it was getting a bit slow by comparison a few years ago, but now we have 6,2 and 1 clock devices that have addressed that issue. It's down side is handling large amounts of data in ram, but that's only sometimes a problem in certain applications. One of my later projects used a 8051 derivative simply because it had a 24bit a/d converter (aduc834), had this not been the case I may have used an AVR.

Last week I designed in a MC68HC908QY4 into a simple project because it was 5V,4k flash,on chip oscillator and had a free 'c' compiler (metroworks) and was dirt cheap.

One company I worked for used PIC's exclusively - simply because Microchip gave this (very very large) company special pricing so no one else could compete.


Once you have experience with a microcontroller, learning another is relatively easy. You are not doing yourself an injustice starting with an 8051.

Who uses 8051's?

Allen Bradley use a Dallas 80c320 micro in their smaller PLC's
Bosch used to use a lot of 8051s in their earlier ECU's and ABS controllers for cars.
I saw a 8051 in one of GE's old mobile phones!