LR1110
User Manual
Rev.1.0
UM.LR1110.W.APP
March 2020
30 of 130
Semtech
4. GPIOs
The LR1110 features 12 digital IOs:
•
DIO1 to DIO4 are dedicated to the SPI interface signals NSS, SCK, MOSI and MISO respectively.
•
DIO0 is used as BUSY signalling, and is mandatory to properly handle the host controller interface.
•
DIO9 is dedicated to the LR1110 interrupts. It is recommended to connect DIO9 to the host controller for the
lowest-power applications. DIO11 can be used as another interrupt pin if no 32.768 kHz crystal oscillator is used.
•
NRESET allows to cancel on-going functions of the LR1110, and reset all HW and FW. Although a device restart is also
possible through host controller commands, it is recommended to allow the host controller to control this signal.
•
DIO5, DIO6, DIO7, DIO8 and DIO10 can be used to control external RF switches or LNAs on the Wi-Fi, GNSS, and
sub-GHz RF paths.
•
DIO8 can also be used as 32.768 kHz source to the host controller if a 32.768 kHz crystal oscillator is connected to
DIO10 and DIO11.
•
DIO10 and DIO11 can be used as connection pins for an external 32.768 kHz crystal oscillator as RTC source. DIO11 can
also be used as input pin in case the 32.768 kHz signal is fed by the host controller. In that case DIO10 shall be left
unconnected.
4.1 Interrupts
The LR1110 features numerous interrupt sources, allowing the host to react to a large variety of events in the LR1110 system
without the need to poll registers, and therefore allowing power-optimized applications.
4.1.1 Description
The LR1110 interruptions are multiplexed on DIO9 and/or DIO11 pin. When the application receives an interrupt, it can
determine the source by using the command
GetStatus( )
. The interrupt can then be cleared using the
ClearIrq( )
command.
The command
SetDioIrqParams( )
configures which interrupt signal should be activated on the DIO9 and/or DIO11 interrupt
pins.
The interrupts mapping table
IrqToEnable
is as follows:
Table 4-1: IrqToEnable Interruption Mapping
Bit
Interrupt
Description
0
RFU
RFU
1
RFU
RFU
2
TxDone
Packet transmission completed
3
RxDone
Packet received
4
PreambleDetected
Preamble detected
5
SyncWordValid / HeaderValid
Valid sync word / LoRa® header detected
6
HeaderErr
LoRa® header CRC error
