The RenesasR8C is a 16-bit microcontroller that was developed as a smaller and cheaper version of the Renesas M16C . It retains the M16C's 16-bit CISC architecture and instruction set, but trades size for speed by cutting the internal data bus from 16 bits to 8 bits. It is available in a number of different versions with varying amounts of flash memory and SRAM.
All R8C have an internal ring oscillator and can be used without an external resonator. Common interfaces are UART and some devices have CAN interfaces. Some devices have an internal data flash which is meant as a replacement for a serial EEPROM, although it handles less write cycles as a real serial EEPROM. R8C devices have OCD (On Chip Debugging, see In-circuit emulator). When debugging with the Renesas E8 debugger or E8a debugger, UART 1 cannot be used. The debug interface uses only four wires: Vcc, GND, Reset and Mode.