MIKROE-972 mikroElektronika, MIKROE-972 Datasheet - Page 22

• Manufacturer Part Number: MIKROE-972
• Description: Development Boards & Kits - ARM EASYMX PRO v7 ARM STELLARIS CORTEX-M3
• Manufacturer: mikroElektronika

Specifications of MIKROE-972

• Rohs: yes
• Product: Development Boards
• Tool Is For Evaluation Of: LM3S9B95
• Core: ARM Cortex M3
• Interface Type: CAN, I2C, SPI
• Operating Supply Voltage: 7 VAC to 23 VAC, 9 VDC to 32 VDC

USB-UART A
page 22
Enabling USB-UART A
In order to enable USB-UART A
communication you must push
SW10.1 (PA1) and SW10.2 (PA0)
to ON position. This connects the
RX and TX lines to PA0 and PA1
microcontroller pins.
DATA BUS
PA1
PA0
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
(CN7), 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 SW10.1 and SW10.2.
SW10
Figure 8-1:
USB-UART A
connection
schematic
TX-FTDI1
RX-FTDI1
VCC-3.3V
10
11
12
13
14
1
2
3
4
5
6
7
8
9
VCC-3.3V
U2
FT232RL
TXD
DTR#
RTS#
VCCIO
RXD
RI#
GND
NC
DSR#
DCD#
CTS#
CBUS4
CBUS2
CBUS3
C3
100nF
FT232RL
VCC-5V
C4
100nF
RESET#
3V3OUT
USBDM
USBDP
CBUS0
CBUS1
OSCO
AGND
VCC-5V
OSCI
TEST
GND
GND
VCC
NC
E1
10uF
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC-5V
RX-LED1
TX-LED1
DVD://download/eng/software/development-tools/
universal/ftdi/vcp_drivers.zip
VCC-3.3V
C11
100nF
Drivers can be found on
R11
2K2
LD7
RX
FTDI1-D_N
FTDI1-D_P
Stellaris
VCC-3.3V
In order to use USB-UART A module on EasyMx PRO
R12
4K7
LD8
TX
®
, you must first install FTDI drivers on your computer.
R18
4K7
R19
10K
Product DVD:
VCC
D-
D+
GND
1
2
3
4
CN7
USB B
EasyMx PRO
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