The S3C9654/C9658/P9658 single-chip 8-bit microcontroller is fabricated using an advanced CMOS process. It is built around the powerful SAM88RCRI CPU core. Stop and Idle power-down modes were implemented to reduce power consumption. To increase on-chip register space, the size of the internal register file was logically expanded. The S3C9654/C9658/P9658 has 4/8 Kbytes of program memory on-chip (S3C9654/C9658), and 208 bytes of RAM including 16 bytes of working register. Using the SAM88RCRI design approach, the following peripherals were integrated with the SAM88RCRI core: -- Three configurable I/O ports (14 pin, at 20 pin) -- 14-bit programmable pins for external interrupts (at 20 pin) -- 8-bit timer/counter with two operating modes