No, we haven't. I took a quick look at their datasheet, and from this quick look, I can see that the pinout is different, they have a wider voltage range, they are slower by about 3X, have 1/2 half the RAM, and they don't have byte erase/program of the user code effectively giving you "EEPROM" use of your code array. Of course, the pinouts are different. The fab process used to build the LPC900 is a 3V process which means that we'd need to use some sort of internal regulator (often a dc/dc converter) to make it a "5V part". We also use some specific pin arrangements on the LPC900 family, such as VSS and VDD pins in the center of the package. This reduces the package inductance compared to the more traditional "corner pins" approach that we all grew up with. Hopefully, it reduces EMI as well. If you compare all of our LPC900 parts, from the 904 on up, you will find that they all have the same relative relationship for five pins: RST, VSS, P0.4,P0.5, and VDD in the TSSOP packages. This is by intention. These are the pins that are used for ICP programming. By keeping them in the same relative positions, inexpensive programmer vendors are able to program everything with simple adapters or no adapters at all. The 5V I can't easily solve. We did do some of the 8-pin devices (901/2/3) in a Microchip compatible pinout.