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14. USING THE DEVELOPER’S KIT
74
LZT 123 7589 R1A
14.3 Jumpers
All jumpers are located on the developer’s board (see “Developer’s board
overlay”, page 73).
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Jumper Default Description
INT/EXT INT Selects which voltage path supplies the DK support
circuitry (not the supply to the radio device).
INT selects power from the internal +3.6V DC supply.
EXT selects power from the EXT VCC connector.
TO_IN - With jumper TO_IN fitted, the DK and the radio device
will automatically power-up as soon as power is
applied to DC Jack X9.
SHDN - With jumper SHDN fitted, the internal +3.6V power
supply will be disabled.
Note: There is a second jumper labelled ’SHDN’ which
is in the UART area (by X4).
VRTC Fitted This jumper connects the DK real-time-clock backup
capacitor to the VRTC pin of the radio device.
Jumper Default Description
SRVC - When fitted, the module will be operated in ’Service’
mode enabling system-status logging from the radio
device.The red ‘Service’ LED will be illuminated.
PORT - When fitted, switches the serial port from the 'AT'
command port UART1 to UART2/UART3.
Note: Use the PORT jumper link in conjunction with
links “TD2/TD3” and “RD2/RD3” to select between
UART2/UART3.
TD2/TD3 - This dual jumper selects the TD (Transmit Data) line for
either UART2 or UART3 as the alternative serial port
when jumper 'PORT' is fitted. The jumper connects
TD2 or TD3 to the centre pin to make the selection.
See “Connectors”, page 80 for more details.
Note: When UART2 or UART3 is used via the
application connector, the TD2 or TD3 jumper must
be removed to avoid circuit conflicts within the DK.
RD2/RD3 - This dual jumper selects the RD (Receive Data) line
for either UART2 or UART3 as the alternative serial port
when jumper 'PORT' is fitted. The jumper connects
RD2 or RD3 to the centre pin to make the selection.
See “Connectors”, page 80 for more details.
Note: When UART2 or UART3 is used via the
application connector, the RD2 or RD3 jumper must
be removed to avoid circuit conflicts within the DK.