Interrupt Control
The standard 8051 and AT89C2051 provide six interrupt sources:
Each interrupt is assigned a fixed location in memory and an interrupt causes the CPU tojump tothat location, where it executes the interrupt service routine. Table 1.5 gives the interrupt sources and the start of their service routines in memory. Note that the serial port receive and transmit interrupts point to the same location.
Each interrupt source can be individually enabled or disabled by setting or clearing its interrupt enable bit. Table 1.6 gives the interrupt enable bit patterns.