Datasheet

Table Of Contents
Functional overview STM32WLE5J8/JB/JC
18/135 DS13105 Rev 4
3.8.2 General description
The sub-GHz radio provides an internal processing unit to handle communication with the
system CPU. Communication is handled by commands sent over the SPI interface, and a
set of interrupts is used to signal events. BUSY information signals operation activity and is
used to indicate when the sub-GHz radio commands cannot be received.
The block diagram of the sub-GHz radio system is shown in the figure below.
Figure 2. sub-GHz radio system block diagram
3.8.3 Transmitter
The transmit chain comprises the modulated output from the modem, that directly
modulates the RF-PLL. An optional pre-filtering of the bit stream can be enabled to reduce
the power in the adjacent channel also dependent on the selected modulation scheme. The
modulated signal from the RF-PLL directly drives the high output power PA (HP PA) or low
output power PA (LP PA).
Transmitter high output power
Transmit high output power up to + 22 dBm, is supported through the RFO_HP RF pin. The
HP PA can be supplied from the PA regulator (REG PA) up to 3.1 V.
MSv62615V1
Note: LoRa modem is only available on STM32WLE5xx devices.
Sub-GHz radio
Sub-GHz
RF frontend
Radio
control
SUBGHZSPI
hse32
Interrups
RFO_LP
RFO_HP
RFI_P
RFI_N
FSK
modem
LoRa
modem
(note)
Data
and
control
HSE32
OSC_IN
OSC_OUT
BUSY
HSERDY
HSEON
HSEBYPPWR
VR_PA
VDDPA
PB0_VDDTCXO