I started programming at the age of 13 with BASIC on my first computer, a Sharp PC-1403H. Although at that time it was forbidden to use programmable calculators at school, I still used it and wrote small programs for subjects like math and science for it. Nobody knew what it was, anyway.
Three years later we were allowed to use graphical and programmable calculators for school. Since I already knew and liked what Sharp built I bought a PC-E500S for which I wrote dozens of useful and not-so-useful and not-quite-working programs, among them some games, a simple machine language monitor, a loadable menu system for BASIC programs including a menu editor and a program for drawing simple diagrams. I tried to learn how to program it in assembly language, but I never had much success. In 2003 the machine died because of failing RAM after I hadn't really used it for three years.
In 2001 I bought a PC-E220 at eBay, paying a ridiculous price. It was advertised as having a Z80-compatible CPU and being designed to be programmed in assembly language. I was, however, disappointed that its manual didn't tell me anything useful about the machines internals. For this reason I decided to write a disassembler for disassembling its ROM contents to find out how to access the hardware from assembly language programs. While I finished the disassmbler, I actually never had the time to disassemble the ROM contents.
After three years of looking for information on this machine on the Net without any success, finally some really useful in-depth information on the PC-E220 has shown up here.