Datasheet

DocID026906 Rev 3 11/27
SP1ML Hardware design
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2.2 Typical application circuit
In a typical application the SP1ML module is connected to a host MCU using a standard
UART, with transmit and receive signals. This is illustrated in Figure 3.
Figure 3. Typical application circuit
Optional functionality
1. When the TXRX_LED (S24) configuration register (see Table 10) is set to 1, the
TXRXLED signal is an active-low open drain output that can be used to drive an
external LED for status indication when data is sent or received.
2. The MODE0 signal provides a hardware method for switching between command and
operating modes. The SHDN signal allows the module to be placed into a low power
shutdown mode and woken up again.
3. The BOOTMODE AND RESET signals should be connected if module firmware will
need to be updated over the UART interface.
4. To support custom module firmware, the serial wire debug signals need to be
accessible for programming and debugging.
2.3 Layout guidelines
The application PCB requires a flooded ground plane. Care must be taken to ensure there
are no traces or ground planes under the area surrounding the antenna, with the exception
SP1ML
MODULE
HOST
MCU
TXD TXD
RXD RXD
RTS
CTS
GPIO
GPIO
BOOTMODE
RESET
GPIO
GPIO
MODE0
SHDN
TXRXLED
1
2
3
VDD
RESET
SWCLK
SWDIO
4
SWD
HEADER
VDD
VDD
VDD
GND
10uF