User`s guide

1/15/03 6-1
Chapter 6
I/O Ports
The LZ87010 has seven 8-bit general-purpose I/O ports and two 8-bit high-current
output ports. These ports are read and written under software control. Most ports are bit-
addressable, allowing individual bits to be set or cleared without disturbing the other bits
in the port.
Most of the general-purpose I/O pins are shared with other functions. In general, all func-
tions sharing a pin are simultaneously active, and it is up to the programmer to ensure that
functions not desired at the moment are not driving their output pins.
The nine ports have mnemonics PORT0 through PORT9. They are also called P0 through
P9. PORT4 is not implemented on the LZ87010.
Figure 6-1. General-Purpose I/O Port (One Bit Shown)
LZ87010-82
DQ
CLK
I/O PIN
DATA
OUT
CCLK
DATA
IN
VDD
90 kΩ
EXTERNAL TO
THE LZ87010
INTERNAL TO
THE LZ87010