Table 7-1 Gpio Pin Configuration; Gpior Data Bits (Gd[3:0])—Bits 3–0 - Motorola DSP56009 User Manual

General Purpose Input/Output
GPIO Register (GPIOR)
7.3.1 GPIOR Data Bits (GD[3:0])—Bits 3–0
The read/write GPIO Data bits (GD[3:0]) are used to read from or write to the
corresponding GPIO[3:0] pins. If the GPIOx pin is defined as an input, the GDx bit
will reflect the logic value present on the GPIOx pin. If the GPIOx pin is defined as an
output, the GPIOx pin will reflect the value written to the GDx bit. The GD[3:0] bits
are cleared during hardware reset and software reset.
7.3.2 GPIOR Reserved Bits—Bits 4–7, 12–15, and 20–23
These bits are reserved and unused. They read as 0s and should be written with 0s
for future compatibility.
7.3.3 GPIOR Data Direction Bits (GDD[3:0])—Bits 11–8
The read/write GPIO Data Direction bits (GDD[3:0]) select the direction of data
transfer for each of the GPIO[3:0] pins (see Table 7-1 ). When the GDDx bit is cleared,
the corresponding GPIOx pin is defined as an input. When the GDDx bit is set, the
corresponding GPIOx pin is defined as an output. The GDD[3:0] bits are cleared
during hardware reset and software reset.
GDDx
0
0
1
1
7.3.4 GPIOR Control Bits (GC[3:0])—Bits 19–16
The read/write GPIO Control bits (GC[3:0]) select the type of output buffer for each
of the GPIO[3:0] pins when the pins are defined as outputs, and select whether or not
the input buffer is connected to the pin when the pin is defined as an input.
7-4

Table 7-1 GPIO Pin Configuration

GCx
0 Disconnected
1 Input
0 Standard active high/active low output
1 Open-drain output
DSP56009 User's Manual
GPIO Pin Definition
MOTOROLA