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modules/bluetooth-modules
15
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Table 2: USB U4 USB-SWD to BL654PA SWD signal routing connections
SW3 Reset Button
into Analog switch
U25 (net name)
USB Cable Plugged into USB2
(USB_DETECT HIGH)
No USB cable plugged into
USB2 (USB_DETECT LOW)
Comments
Route SW3 Reset Button to
BL654PA (U5) Reset Pin
via Analog Switch U25
(net name)
Route SW3 reset button to
BL654PA (U5) reset pin
via analog switch U25
BOOT_RESET_BLE
nRESET_BLE
nRESET_BLE
R114 0R resistor, if removed,
allows SW3 to be disconnected
from BL654PA reset pin when
USB2 cable plugged in.
The development board provides access to the BL654PA module two-wire SWD interface on JP1 via analog switch U24. This
is
required
for customer use, since the BL654PA module supports
smart
BASIC runtime engine firmware over JTAG (as well
as over UART).
Note:
We recommend that you use JTAG (two-wire interface) to handle future BL654PA module firmware upgrades. You
must
wire out the JTAG (two-wire interface) on your host design (four lines should be wired out, namely SWDIO,
SWDCLK, GND, and VCC). Firmware upgrades can still be performed over the BL654PA UART interface, but this is
slower (60 seconds using UART vs. 10 seconds when using JTAG) than using the BL654PA JTAG (two-wire
interface).
Upgrading
smart
BASIC runtime engine firmware or loading
smart
BASIC applications also can be done using the UART
interface.
For those customers (using Nordic SDK) that require access to BL654PA SWD (JTAG) interface, the BL654PA development
board (see
) has on-board circuitry to allow access to BL654PA module SWD interface (via USB connector USB2).
Figure 8: SWD on-board circuitry routing via analog switch U24
When the USB cable is plugged into connector USB2, the USB cable detection output generates a HIGH for USB_DETECT
and USB_DETECTp when switch SW11 is in position 2-1 (default) and Atmel MCU SWD (JTAG) signals are routed to the
BL654PA SWD interface. This is required to connect the two-wire SWD (JTAG) interface from U14 to the BL654PA SWD
(JTAG) interface.
When the USB cable is plugged into connector USB2 and the SW11 is in position 2-3 (Low), there is a LOW on U24 control
line USB_DETECTp and the Atmel MCU SWD (JTAG) signals are routed to connector JP1 (which is not populated).
Figure 9: SW11 on development board (showing default position)
GND
SWDIO_EXT
SWDCLK_EXT
JP1
NOPOP (PIN HEADER,1.27mm 2X5P)
1
2
3
4
5
6
7
8
9
10
nRESET_EXT
SWO_EXT
VDD_VSRC_nRF
Содержание BL654PA
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