
THE 8051 MICROCONTROLLER: THE PROGRAMMER’S PERSPECTIVE 485
Data Pointer (DPTR) is is also an address register, and so it is 16 bits in size. However,
it can be used as two 8-bit registers—DPH and DPL, with H and L standing for high
and low respectively, that is, the MSB and LSB of the DPTR. See Figure 13.5.
e DPTR is used as a pointer for accessing internal ROM, and also for external
memory (if added to the chip).
13.2.4 | Ports
ere are four 8-bit ports for 8051, and they are named 0 to 3. ere are corresponding
port pins, and these are used to connect to the peripherals. e ports are designated as
P0, P1, P2 and P3 and can be used ...