Maxim Integrated DS4830A Optical Microcontroller - Manual (Page 138)

DS4830A User’s Guide
138
SECTION 15 – GENERAL-PURPOSE INPUT/OUTPUT (GPIO) PINS
15.1 – Overview
The DS4830A provides general-purpose input/output (GPIO) functionality on 31 pins. In addition to the GPIO
functionality, each of these pins is multiplexed with at least one other function, which is classified as “Special
Function.”
Special functions override the GPIO register settings of the port pin when they are enabled. Once the special
function takes control, normal control of the port pin is lost until the special function is disabled.
Table 15-1 details all of the GPIO pins as well as what other functions are multiplexed with each pin. With the
exception of a few pins which are described further in detail later, the GPIO pins operate as shown in the GPIO Pin
Block Diagram, Figure 15-1. Some of the features of these GPIO pins are:
• CMOS output drivers
• Schmitt trigger inputs
• Optional weak pullup to V
DD
when operating in input mode
V
DD
VDD
MUX
I/O PAD
PDp.n
SF DIRECTION
SF ENABLE
POp.n
WEAK
MUX
SF OUTPUT
DETECT
CIRCUIT
*
*
DS4830A Pin
SF = SPECIAL FUNCTION
THE FORMAT FOR GPIO CONTROL BITS SHOWN IS PDp.n
‘p’ designates the port (p=0,1,2,6)
‘n’ is the port pin (n=0 to 7).
PIp.n, or SF INPUT
INTERRUPTS ON ALL PORTS
EIFp.n EIEp.n
EIESp.n
Figure 15-1: GPIO Pin Block Diagram