
© Copyright ARM Limited 2016. All rights reserved.
WH000
ARM-EPM-1017464.0
Confidential
Page 11
3.3.4
UART/SWD Jumpers:
The four UART/SWD Jumpers (J6-
9) allow the BT4 SoC’s Host UART and Serial Wire Debug (SWD) interfaces to
be switched between the mbed controller and connector headers for external communications.
“UART/SWD jumpers” (J6-9) are located above the USB connector on the bottom left side of the board. Placing all
4 of the jumpers in their top position (marked “Header”) will connect the BT4 SoC Host UART to the J5 UART
header just to the right of USB connector. This is the default position that is used in most applications. This
position allows serial communications with Test equipment and PCs running ARM
’s Radio Control Tool via J14.
Please note that the UART supports 3.3 volt signal level.
A USB to UART cable is provided in the Kit that
supports 3.3 volt signal level.
If you are connecting the Eval board to the RS-232 port of test equipment, you
will need to install a signal level shifting cable or adapter!
Placing these jumpers in the lower
“
mbed
”
position will connect the SWD and UART interfaces to the mbed
controller. This is used for drag-n-drop programing of the BT4 SoC
’
s FLASH. (See Section 9 on FW
programming). This also allows support of Keil tools via the USB connector. Please visit
more mbed tools and development community.
The Default positions for these jumpers are to have the UART jumpers (J8 & 9) to be in the top
“
Header
”
position
to allow UART communicates via the J14 UART header. Counter to this, the Serial Wire Debug (SWD) jumpers
(J6 & 7) should be in the lower
“
MBED
”
position to allow for FW updates and other functions as described in
Section 9).
3.3.5
Firmware / Demo Selection Jumpers:
The J19 Firmware/Demo Selection jumpers are located just under the lower right corner of the module. There are
two jumpers that determine the functionality of the board at boot time by loading the appropriate FW for either Test
Mode or Demo Mode. Please see Section 4 for additional information on these FW modes.