4d Systems 2.8" TFT Intelligent Display $LCD-28PTU uLCD-28PTU 数据表
产品代码
uLCD-28PTU
4D SYSTEMS µLCD-28PTU
© 2014 4D SYSTEMS Page 7 of 22 www.4dsystems.com.au
mi
cr
oLC
D
PIC
ASO
DI
SP
LA
Y
4. Hardware Interface - Pins
The μLCD-28PTU provides both a hardware and
software interface. This section describes in detail
the hardware interface pins of the device.
Serial Ports - COM0, COM1 UARTS
The μLCD-28PTU has two dedicated hardware
Asynchronous Serial ports that can communicate
with external serial devices. These are referred to
as the COM0 and the COM1 serial ports.
The primary features are:
•
Full-Duplex 8 bit data transmission and
reception.
reception.
•
Data format: 8 bits, No Parity, 1 Stop bit.
•
Independent Baud rates from 300 baud up to
600K baud.
600K baud.
•
Single byte transmits and receives or a fully
buffered service. The buffered service feature
runs in the background capturing and
buffering serial data without the user
application having to constantly poll any of the
serial ports. This frees up the application to
service other tasks.
buffered service. The buffered service feature
runs in the background capturing and
buffering serial data without the user
application having to constantly poll any of the
serial ports. This frees up the application to
service other tasks.
A single byte serial transmission consists of the
start bit, 8-bits of data followed by the stop bit.
The start bit is always 0, while a stop bit is always
1. The LSB (Least Significant Bit, Bit 0) is sent out
first following the start bit. Figure below shows a
single byte transmission timing diagram.
COM0 is also the primary interface for 4DGL user
program downloads and chip configuration (PmmC
programming).
program downloads and chip configuration (PmmC
programming).
Once
the
compiled
4DGL
application
program
(EVE
byte-code)
is
downloaded and the user code starts executing,
the serial port is then available to the user
application. Refer to Section 5. ‘Firmware / PmmC
Programming’ for more details on this subject.
the serial port is then available to the user
application. Refer to Section 5. ‘Firmware / PmmC
Programming’ for more details on this subject.
TX0 pin (Serial Transmit COM0):
Asynchronous Serial port COM0 transmit pin, TX0.
Connect this pin to external serial device receive
(Rx) signal. This pin is 5.0V tolerant.
RX0 pin (Serial Receive COM0):
Asynchronous Serial port COM0 receive pin, RX0.
Connect this pin to external serial device transmit
(Tx) signal. This pin is 5.0V tolerant.
TX1 pin (Serial Transmit COM1):
Asynchronous Serial port COM1 transmit pin, TX1.
Connect this pin to external serial device receive
(Rx) signal. This pin is 5.0V tolerant.
RX1 pin (Serial Receive COM1):
Asynchronous Serial port COM1 receive pin, RX1.
Connect this pin to external serial device transmit
(Tx) signal. This pin is 5.0V tolerant.
Asynchronous Serial port COM0 transmit pin, TX0.
Connect this pin to external serial device receive
(Rx) signal. This pin is 5.0V tolerant.
RX0 pin (Serial Receive COM0):
Asynchronous Serial port COM0 receive pin, RX0.
Connect this pin to external serial device transmit
(Tx) signal. This pin is 5.0V tolerant.
TX1 pin (Serial Transmit COM1):
Asynchronous Serial port COM1 transmit pin, TX1.
Connect this pin to external serial device receive
(Rx) signal. This pin is 5.0V tolerant.
RX1 pin (Serial Receive COM1):
Asynchronous Serial port COM1 receive pin, RX1.
Connect this pin to external serial device transmit
(Tx) signal. This pin is 5.0V tolerant.
General Purpose I/O
There are 13 general purpose Input/Output (GPIO)
pins available to the user. These are grouped as
IO1..IO5 (Note for IO1, IO2 and IO3 below) and
BUS0..BUS7. Power-Up Reset default is all INPUTS.
The 5 I/O pins (IO1..IO5), provide flexibility of
individual bit operations while the 8 pins
(BUS0..BUS7), known as GPIO BUS, serve
collectively for byte wise operations. The IO4 and
IO5 also act as strobing signals to control the GPIO
Bus. GPIO Bus can be read or written by strobing a
low pulse (50ns duration or greater) the
IO4/BUS_RD or IO5/BUS_WR for read or write
respectively. For detailed usage refer to the
separate document titled:
“PICASO-4DGL-Internal-Functions.pdf”
IO1-IO5 pins (excluding IO3) (2 x GPIO pins):
General purpose I/O pins. Each pin can be
individually set for INPUT or an OUTPUT.
IO1 pin (Frame Mark pin):
The IO1 pin has 2 functions. It can be used as a
GPIO pin but can also be used to detect the start
of a Frame. When used as a GPIO pin, simply
connect an Input/Output to the IO1 pin on the H1
header. When using IO1 for Frame Mark, simply
leave the IO1 pin on the H1 header disconnected,
and read the status of IO1 as an Input.
IO2 pin (Lithium Battery Status pin):
The IO2 pin has 2 functions. It can be used as a
GPIO pin but can also be used to tell when the
Lithium battery has reached a low level (3.7V) and
needs to be charged. When used as a GPIO pin,