I have actually used the 24 bit dual axis encoder chip successfully with the 8051. I might say that the chip does work quite well. I used the chip in a data acquisition scheme in which I took the 24-bit value and divided the value down using a moving window allowing for extremely fast division. The way I hooked up my 8051 was by using a dedicated port for the 8-bit output and sequentially read that port until I got all 24 bits and then pasted them together into a 32 bit buffer. Originally, I used just the 8051 as a counter and this was by all means extremely acurrate, but entirely slow for data acquisition. I switched to this chip and instead of reading each of the encoder inputs I would be polling this chip. Keep in mind that using this chip reqiures a polling methodology and subsequently the dividing of the 24-bit number will never be dead on. If all youre after is the 24-bit number, this is no problem. Also, what do you plan on doing with this number (placing it on an display or trasnferring to a host)? I found that if you just straight transfer the data to a host via serial youll lose a lot of time that could be spent polling. This brings up another point, if you do decide on transferring the data you might want to consider adding a digital buffer so that transfer times do not interfer with polling time. I do not know what exactly you want to hear, but I have been using this chip in the field for over 2 years and I am using the 8051. Another neat idea is that you can make this chip work with complementary inputs from the encoders if the encoders are more than 10 feet away by using some inverters and nor gates. Also, check with the datasheet because on some of these chips oscillators are included, but in some oscillators are not included. The one I used requires a clock source. Good luck.