GENERAL PURPOSE I/O FUNCTIONAL DESCRIPTION
The FDC37C93xFR provides a set of flexible
General Purpose I/O Ports
Input/Output control functions to the system
designer through a set of General Purpose I/O
pins (GPI/O). These GPI/O pins may perform
simple I/O or may be individually configured to
The FDC37C93xFR has 14 dedicated,
independently programmable general purpose
I/O ports (GPI/O).
Each GPI/O port is
provide a predefined
Power-on reset configures all GPI/O pins as
simple non-inverting inputs.
alternate
function.
represented as a bit in one of two GPI/O 8-bit
registers, GP1 or GP2. Only 6 bits of GP2 are
implemented. Each GPI/O port and its alternate
function is listed in Table 50A.
Table 50A - General Purpose I/O Port Assignments
PIN
NUMBER
96
ORIGINAL
FUNCTION
GP10
ALTERNATE
FUNCTION 1
Interrupt Steering*
Interrupt Steering*
WD Timer Output
Power LED
ALTERNATE
FUNCTION 2
ALTERNATE
FUNCTION 3
GPI/O REGISTER
ASSIGNMENT
GP1, bit 0
-
-
-
-
-
-
-
97
98
99
100
GP11
GP12
GP13
GP14
GP1, bit 1
GP1, bit 2
GP1, bit 3
GP1, bit 4
IRRX Input
IRTX Output
-
GP Address
Decoder
102
103
GP15
GP16
GP Write Strobe
Joystick RD Strobe Joystick Chip
Sel
-
-
-
GP1, bit 5
GP1, bit 6
104
GP17
Joystick WR
Strobe
-
-
GP1, bit 7
105
106
GP20
GP21
IDE2 Buffer Enable
Serial EEPROM
Data In *
8042 P20
AB_DATA
-
-
GP2, bit 0
GP2, bit 1
107
108
109
110
GP22
GP23
GP24
GP25
Serial EEPROM
Data Out
Serial EEPROM
Clock
Serial EEPROM
Enable
AB_CLK
-
-
-
-
GP2, bit 2
GP2, bit 3
GP2, bit 4
GP2, bit 5
-
-
-
8042 P21
Note 1: 8042 P21 is normally used for Gate
A20
Note 2: 8042 P20 is normally used for the
Keyboard Reset Output
* These are input-type alternate functions; all
other GPI/O pins contain output-type
alternate functions.
120
SMSC [ SMSC CORPORATION ]
