Migrating from 8051 to ARM

So as long as the 8051 is powerful enough for your needs than you shouldn't move. But if you feels like you needs a change you should move to ARM based architectures for a number of reasons:

• They are dropping RAPIDLY in price
• They are FULLY 32-bit cores, 8-bit MCU's just don't cut it some times. For example my DVD player from 2002 has an 8052 MCU embedded in it as a front end (remote control reading, On Screen Display etc.). But newer DVD players from what I've been seeing are either using proprietary cores or ARM based cores.
• Also budget wireless chipsets and routers use ARM7 and ARM9 chips (probably to do the WEP/WPA encryption). Well I do know the wifi chipset in the PSP uses an ARM9 based CPU.
• Supported by freeware GNU compilers (GCC for example), makes development rather painless and if you want to code in assembly (GNU assembler really sucks ) then you get free assembler.
• Tons of very cheap devkits available (that operated close to 60Mhz, a 60Mhz ARM is a very powerful chip, definitely could do MP3 decoding)
• And of course, the iPod Nano ( and probably all iPod's) uses ARM as a main CPU.
• The ARM is rapidly gaining ground and with their price going downwards each year, they will soon replace most 8-bit in anything but mundane tasks.

Generally when it comes to MCU's:

PIC - Only use for mundane tasks (keyboard reading, image scanning, etc.) because the single cycle architecture makes this stuff easier.

8051 - Use for more complicated tasks, still a bit limited because of the limited stack space. Handles complicated tasks much more elegantly than PIC.

ARM7/9 - Use for complicated tasks that require a lot of code (Video players, MP3 players, etc.). Handles complicated tasks very elegantly and efficiently. Better tuned for embedded C programming.

Of course I skipped many other great MCU architectures but if you are interested you can find some better ones.