General description
The P87C51Mx2 represents the first microcontroller based on Philips Semiconductors’ new 51MX core. The P87C51MC2 features 96 kbytes of OTP program memory and 3 kbytes of data SRAM, while the P87C51MB2 has 64 kbytes of OTP and 2 kbytes of RAM. In addition, both devices are equipped with a Programmable Counter Array (PCA), a watchdog timer that can be configured to different time ranges through SFR bits, as well as two enhanced UARTs and Serial Peripheral Interface (SPI).

Philips Semiconductors’ 51MX (Memory eXtension) core is an accelerated 80C51 architecture that executes instructions at twice the rate of standard 80C51 devices. The linear address range of the 51MX has been expanded to support up to 8 Mbytes of program memory and 8 Mbytes of data memory. It retains full program code compatibility to enable design engineers to re-use 80C51 development tools, eliminating the need to move to a new, unfamiliar architecture. The 51MX core also retains 80C51 bus compatibility to allow for the continued use of 80C51-interfaced peripherals and Application Specific Integrated Circuits (ASICs).