General description
   The P89CV51RB2/RC2/RD2 are three types of 80C51 microcontroller with respectively 16 kB/32 kB/64 kB flash and 1 kB of data RAM. These devices are designed to be drop-in and software-compatible replacements for the popular P89C51RB2/RC2/RD2 devices. Both the In-System Programming (ISP) and In-Application Programming (IAP) boot codes are upward compatible.

FEATUREs
2.1 Principal features
◾ Supports 12-clock (default) or 6-clock mode selection via ISP or parallel programmer
◾ 6-clock/12-clock mode programmable “on-the-fly” by an SFR bit
◾ Peripherals (PCA, timers, UART) may use either 6-clock or 12-clock mode while the
   CPU is in 6-clock mode
◾ 128-B page erase for efficient use of code memory as non-volatile data storage
◾ 0 MHz to 40 MHz operating frequency in 12× mode, 20 MHz in 6× mode
◾ 16/32/64 kB of on-chip flash user-code memory with ISP and IAP
◾ 1 kB RAM
◾ SPI (Serial Peripheral Interface) and enhanced UART
◾ PCA (Programmable Counter Array) with PWM and capture/compare functions
◾ Three 16-bit timers/counters

2.2 Additional features
◾ Four 8-bit I/O ports
◾ WatchDog Timer (WDT)
◾ 30 ms page erase, 150 ms block erase
◾ PLCC44 and TQFP44 packages
◾ Ten interrupt sources with four priority levels
◾ Second DPTR register
◾ Low EMI mode (ALE inhibit)