Datasheet
USB-UART A
Enabling USB-UART A
communication
page 22
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 TX and
RX 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 EasyMx PRO
™
v7 for
STM32, you must rst install FTDI drivers on your computer.
Drivers can be found on Product DVD:
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DVD://download/eng/software/development-tools/
universal/ftdi/vcp_drivers.zip
EasyMx PRO
v7
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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
4K7
R21
10K
1
2
3
4
VCC
GND
D-
D+
CN22
USB B
C6
100nF
C7
100nF
E1
10uF
VCC-5VVCC-5VVCC-3.3V
USB UA RT A
CONNECTOR
FTDI1-D_N
FTDI1-D_P
RX TX
DATA BUS
1 2 3 4 5 6
7
8
O
N
SW12
TX-FTDI1
RX-FTDI1
PA9
PA10
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All other trademarks are the property of their respective owners.
Unauthorised copying, hiring, renting, public performance
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PRODUCT DVD
www.mikroe.com
www.libstock.co m
In order to enable USB-UART A
communication, you must push
SW12.1 (PA9) and SW12.2 (PA10)
to ON position. This connects the
RX and TX lines to PA9 and PA10
microcontroller pins.
Figure 8-1:
USB-UART A
connection
schematic