Laird Lyra S, Руководство пользователя

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The Lyra S Development Kit contains an on-board SEGGER J-Link Debugger that interfaces to the target Lyra S using the
Serial Wire Debug (SWD) interface. The debugger allows the user to download code and debug applications running in the
target Lyra P. Additionally, it also provides a virtual COM port (VCOM) to the host computer that is connected to the target
device's serial port, for general purpose communication between the running application and the host computer. The Packet
Trace Interface (PTI) is also supported by the on-board debugger, which offers invaluable debug information about transmitted
and received packets in wireless links. The on-board debugger is accessible through the USB Micro-B connector.
The on-board debugger is a SEGGER J-Link debugger running on an EFM32. The debugger is directly connected to the
debug and VCOM pins of the target Lyra P.
When the debug USB cable is inserted, the on-board debugger is automatically active and takes control of the debug and
VCOM inter- faces. This means that debug and communication will
not work with an external debugger connected at the same
time. The on-board LDO is also activated which then powers the board. When the USB cable is removed, the on-board
debugger goes into a very low power shutoff mode (EM4S), consuming around 80 nA typically (EFM32GG12 data sheet
number). This means that an application running off batteries will not be affected too much by the on-board debugger power
consumption. Since the I/O voltage rail of the debugger remains powered in the battery-operated mode, the pins connected to
the debug and VCOM interfaces maintain proper isolation and prevent leakage currents.
The virtual COM port is a connection to a UART of the target Lyra S and allows serial data to be sent and received from the
device. The on-board debugger presents this as a virtual COM port on the host computer that shows up when the USB cable is
inserted.
Data is transferred between the host computer and the debugger through the USB connection, which emulates a serial port
using the USB Communication Device Class (CDC). From the debugger, the data is passed on to the target device through a
physical UART connection.
The serial format is 115200 bps, 8 bits, no parity, and 1 stop bit by default. For more information on
Note: Changing the baud rate for the COM port on the PC side does not influence the UART baud rate between the debugger
and the target device.
Schematic, assembly drawing, 3D model are available on the Lyra Series product page in Documentation->Technical
Drawings:
https://www.lairdconnect.com/lyra-series