Microchip Technology AC164337 Data Sheet
2006-2014 Microchip Technology Inc.
DS70000178D-page 77
dsPIC30F1010/202X
6.0
I/O PORTS
All of the device pins (except V
DD
, V
SS
, MCLR and
OSC1/CLKI) are shared between the peripherals and
the parallel I/O ports.
the parallel I/O ports.
All I/O input ports feature Schmitt Trigger inputs for
improved noise immunity.
improved noise immunity.
6.1
Parallel I/O (PIO) Ports
When a peripheral is enabled and the peripheral is
actively driving an associated pin, the use of the pin as
a general purpose output pin is disabled. The I/O pin
may be read, but the output driver for the parallel port
bit will be disabled. If a peripheral is enabled, but the
peripheral is not actively driving a pin, that pin may be
driven by a port.
actively driving an associated pin, the use of the pin as
a general purpose output pin is disabled. The I/O pin
may be read, but the output driver for the parallel port
bit will be disabled. If a peripheral is enabled, but the
peripheral is not actively driving a pin, that pin may be
driven by a port.
All port pins have three registers directly associated
with the operation of the port pin. The data direction
register (TRISx) determines whether the pin is an input
or an output. If the data direction bit is a ‘1’, then the pin
with the operation of the port pin. The data direction
register (TRISx) determines whether the pin is an input
or an output. If the data direction bit is a ‘1’, then the pin
is an input. All port pins are defined as inputs after a
Reset. Reads from the latch (LATx), read the latch.
Writes to the latch, write the latch (LATx). Reads from
the port (PORTx), read the port pins, and writes to the
port pins, write the latch (LATx).
Reset. Reads from the latch (LATx), read the latch.
Writes to the latch, write the latch (LATx). Reads from
the port (PORTx), read the port pins, and writes to the
port pins, write the latch (LATx).
Any bit and its associated data and control registers
that are not valid for a particular device will be
disabled. That means the corresponding LATx and
TRISx registers and the port pin will read as zeros.
that are not valid for a particular device will be
disabled. That means the corresponding LATx and
TRISx registers and the port pin will read as zeros.
When a pin is shared with another peripheral or func-
tion that is defined as an input only, it is nevertheless
regarded as a dedicated port because there is no
other competing source of outputs.
tion that is defined as an input only, it is nevertheless
regarded as a dedicated port because there is no
other competing source of outputs.
A Parallel I/O (PIO) port that shares a pin with a periph-
eral is, in general, subservient to the peripheral. The
peripheral’s output buffer data and control signals are
provided to a pair of multiplexers. The multiplexers
select whether the peripheral or the associated port
has ownership of the output data and control signals of
the I/O pad cell. Figure 6-1 shows how ports are shared
with other peripherals, and the associated I/O cell (pad)
to which they are connected. Table 6-1 and Table 6-2
show the register formats for the shared ports, PORTA
through PORTF, for the dsPIC30F1010/2020 and
PORTA through PORTG for the dsPIC30F2023 device,
respectively.
eral is, in general, subservient to the peripheral. The
peripheral’s output buffer data and control signals are
provided to a pair of multiplexers. The multiplexers
select whether the peripheral or the associated port
has ownership of the output data and control signals of
the I/O pad cell. Figure 6-1 shows how ports are shared
with other peripherals, and the associated I/O cell (pad)
to which they are connected. Table 6-1 and Table 6-2
show the register formats for the shared ports, PORTA
through PORTF, for the dsPIC30F1010/2020 and
PORTA through PORTG for the dsPIC30F2023 device,
respectively.
FIGURE 6-1:
BLOCK DIAGRAM OF A SHARED PORT STRUCTURE
Note: This data sheet summarizes features of this group
of dsPIC30F devices and is not intended to be a complete
reference source. For more information on the CPU,
peripherals, register descriptions and general device
functionality, refer to the “dsPIC30F Family Reference
Manual” (DS70046).
of dsPIC30F devices and is not intended to be a complete
reference source. For more information on the CPU,
peripherals, register descriptions and general device
functionality, refer to the “dsPIC30F Family Reference
Manual” (DS70046).
Q
D
CK
WR LAT +
TRIS Latch
I/O Pad
WR Port
Data Bus
Q
D
CK
Data Latch
Read LAT
Read Port
Read TRIS
1
0
1
0
WR TRIS
Peripheral Output Data
Output Enable
Peripheral Input Data
I/O Cell
Peripheral Module
Peripheral Output Enable
PIO Module
Output Multiplexers
Output Data
Input Data
Peripheral Module Enable