Maxim Integrated MAX31782 - Manual (Page 96)

  MaximIntegrated 11-2
MAX31782 User’s Guide
Revision 0; 8/11
SECTION 11: GENERAL-PURPOSE INPUT/OUTPUT (GPIO) PINS
The MAX31782 provides general-purpose input/output (GPIO) functionality on 21 pins . In addition to the GPIO function-
ality, each of these pins is multiplexed with at least one other function, which is classified as either a special function
or alternate 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 .
Alternate functions operate in parallel with the GPIO register settings for the port pin, and generally consist of input-only
functions . When an alternate function is enabled for a port pin, the port pin’s output state can still be controlled by the
GPIO register settings, or driven by external hardware .
Table 11-1 details all the GPIO pins as well as what other functions are multiplexed with each pin . With the exception
of a few pins, which are described in further detail later, the GPIO pins operate as shown in the GPIO block diagram
(
Figure 11-1 ) . Some of the features of these GPIO pins include the following:
• CMOS output drivers
• Schmitt trigger inputs
• Optional weak pullup to V
DD
when operating in input mode
Figure 11-1. GPIO Pin Block Diagram
PDp.n
SF = SPECIAL FUNCTION
AF = ALTERNATE FUNCTION
THE FORMAT FOR GPIO CONTROL BITS SHOWN IS PDp.n, WHERE
p DESIGNATES THE PORT (p = 1, 2, 6)
n IS THE PORT PIN (n = 0 TO 7)
SF ENABLE
POp.x
PIp.n , SF INPUT, OR AF INPUT
SF OUTPUT
SF DIRECTION
V DD
I/O PAD
MUX
MUX
MAX31782
PIN
V DD
WEAK*
*THE pMOS AND WEAK PULLUP TRANSISTORS ARE NOT CONNECTED
TO THE SCL, SDA, MSCL, AND MSDA PINS.
*
EIF6.m
INTERRUPTS ONLY FOR PORT6
EIE6.m
EIES6.m
DETECT
CIRCUIT
MAX31782