HPC16003 datasheet(14/36 Pages) NSC

14 / 36 page

PortsAB

The highly flexible A and B ports are similarly structured

The Port A (see

Figure 11 ) consists of a data register and a

direction register Port B (see

Figures 12 13 14 ) has an

alternate function register in addition to the data and direc-

tion registers All the control registers are readwrite regis-

ters

The associated direction registers allow the port pins to be

individually programmed as inputs or outputs Port pins se-

lected as inputs are placed in a TRI-STATE mode by reset-

ting corresponding bits in the direction register

A write operation to a port pin configured as an input causes

the value to be written into the data register a read opera-

tion returns the value of the pin Writing to port pins config-

ured as outputs causes the pins to have the same value

reading the pins returns the value of the data register

Primary and secondary functions are multiplexed onto Port

B through the alternate function register (BFUN) The sec-

ondary functions are enabled by setting the corresponding

bits in the BFUN register

TLDD8801 – 13

FIGURE 11 Port A IO Structure

TLDD8801 – 14

FIGURE 12 Structure of Port B Pins B0 B1 B2 B5 B6 and B7 (Typical Pins)

HPC16003 Datasheet(PDF) 14 Page - National Semiconductor (TI)