Datasheet

page 22
v7
USB-UART A
Enabling USB-UART A
communication
The UART (universal asynchronous receiver/trans-
mitter) is one of the most common ways of exchanging
data between the MCU and peripheral components. It is a serial
protocol with separate transmit and receive lines, and can be used for
full-duplex communication. Both sides must be initialized with the
same baud rate, otherwise the data will not be received correctly.
Modern PC computers, laptops and notebooks are no longer
equipped with RS-232 connectors and UART controllers. They
are nowadays replaced with USB connectors and USB
controllers. Still, certain technology enables UART
communication to be done via USB connection.
Controllers such as FT232RL from FTDI convert
UART signals to the appropriate USB standard.
USB-UART A communication is being done
through a FT232RL controller, USB connector
(CN22), and microcontroller UART module. To
establish this connection, you must connect RX and
TX lines of the FT232RL to the appropriate pins of
the microcontroller. This selection is done using DIP
switches SW12.1 and SW12.2.
In order to use USB-UART A module on EasyPIC Fusion
™
v7,
you must rst install FTDI drivers on your computer. Drivers can
be found on link bellow:
1
2
3
4
5
6
7
8
9
10
11
12
13
14 15
16
17
18
19
20
21
22
23
24
25
26
27
28
TXD
DTR#
RTS#
VCCIO
RXD
RI#
GND
NC
DSR#
DCD#
CTS#
CBUS4
CBUS2
CBUS3
CBUS0
CBUS1
OSCO
OSCI
TEST
AGND
NC
GND
GND
VCC
RESET#
3V3OUT
USBDM
USBDP
FT232RL
U2
FT232RL
VCC-3.3V VCC-5V
C11
100nF
LD69 LD70
RX-LED1
TX-LED1
R15
4K7
R14
2K2
VCC-3.3V VCC-3.3V
R18
1K0
R21
2K2
1
2
3
4
VCC
GND
D-
D+
CN22
USB B
C6
100nF
C7
100nF
E1
10uF
VCC-5VVCC-5VVCC-3.3V
US B UA RT A
CONNECTOR
FTDI1-D_N
FTDI1-D_P
RX TX
1
2 3 4 5 6 7 8
O
N
SW12
TX-FTDI1
RX-FTDI1
RF5
RF4
DATA BUS
In order to enable USB-UART A
communication you must push
SW12.1 and SW12.2 to ON
position. This connects the RX
and TX lines to RF5 and RF4
microcontroller pins.
Figure 8-1:
USB-UART A
connection
schematic
http://www.ftdichip.com/Drivers/VCP.htm