P89C61X2

The Philips microcontrollers described in this data sheet are high-performance static 80C51 designs. P89C60X2 and P89C61X2 are manufactured in an advanced CMOS process and contain a non-volatile Flash program memory that is programmable in parallel (via a parallel programmer) or In-System Programmable (ISP) via boot loader. They support both 12-clock and 6-clock operation.
The P89C60X2 and P89C61X2 contain 512 bytes RAM and 1024 bytes RAM respectively, 32 I/O lines, three 16-bit counter/timers, a six-source, four-priority level nested interrupt structure, a serial I/O port for either multi-processor communications, I/O expansion or full duplex UART, and on-chip oscillator and clock circuits.
In addition, the P89C60X2 and P89C61X2 are static designs which offer a wide range of operating frequencies down to zero. Two software selectable modes of power reduction !" idle mode and power-down mode  are available. The idle mode freezes the CPU while allowing the RAM, timers, serial port, and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator, causing all other chip functions to beinoperative. Since the design is static, the clock can be stopped without loss of user data. Then the execution can be resumed from the point the clock was stopped.