The program in Listing 1 uses a pseudo-RETI instruction to provide a five-priority-level interrupt system for the 8051P microcontroller. The interrupt-priority order, from high to low, is INT0 IT0 ...

The 8051-compatible microcontrollers are equipped with up to two inputs that may be used as general-purpose interrupts. A simple way to increase the number of interrupt inputs is shown in the figure.

The DS89C4x0 single-cycle 8051 processors come with flash memories up to 64 kbytes. They can be programmed by an application. The devices also include two full-duplex UARTs, 13 interrupt sources ...

Taiwanese chip maker Nuvoton Technology has announced a 24MHz 8051-style series of MCUs for industrial automation, motor control, LED dimming and home appliances.