Data Sheet

RM1xx LoRa/BLE Modules
Datasheet
https://connectivity.lairdtech.com/wireless-
modules/lorawan-solutions
12
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The RM1xx module is delivered with the integrated smartBASIC runtime engine FW loaded (but no onboard smartBASIC
application script). Because of this, it starts up in AT command mode by default.
At reset, all SIO lines are configured as the defaults shown above.
SIO lines can be configured through the smartBASIC application script to be either inputs or outputs with pull-ups or pull-
downs. When an alternative SIO function is selected (such as I2C or SPI), the firmware does not allow the setup of internal
pull-up/pull-down. Therefore, when I2C interface is selected, pull-up resistors on I2C SDA and I2C SCL MUST be connected
externally as per I2C standard.
UART_RX, UART_TX, UART_CTS are Vcc logic levels (if VCC is 3.3 V, i.e. SIO pin I/O levels track VCC). For example, when RX
and TX are idle, they sit at 3.3 V (if VCC is 3.3 V). Conversely, handshaking pins CTS and RTS at 0 V are treated as assertions.
Pin 6 (nAutoRUN) is an input, with active low logic. In the development kit (DVK-RM1xx-SM) it is connected so that the state
is driven by the host’s DTR output line. The nAutoRUN pin must be externally held high or low to select between the
following two operating modes:
 Self-contained Run mode (nAutoRUN pin held at 0 V).
 Interactive/development mode (nAutoRUN pin held at VCC).
smartBASIC runtime engine firmware checks for the status of nAutoRUN during power-up or reset. If it is low and if there is
a smartBASIC application script named $autorun$, then the smartBASIC runtime engine FW executes the application script
automatically; hence the name Self-contained Run Mode.
3.3 Electrical Specifications
3.3.1 Absolute Maximum Ratings
Absolute maximum ratings for supply voltage and voltages on digital and analogue pins of the module are listed below;
exceeding these values causes permanent damage (Table 3).
Table 3: Maximum Current Ratings
Parameter Minimum Maximum Unit
Voltage at VCC_BLE and VCC_LORA pin
-0.3 +3.6 (Note 1) V
Voltage at GND pin
0 V
Voltage at SIO pin
-0.3 VCC+0.3 V
Storage temperature
-40 +85 ºC
Note 1: Absolute Max Rating for VCC pin (max) is 3.6V, however we recommend 3.3V +/-5% as the spec for maximum
Vcc. The LoRa transmitter shuts down if the voltage exceeds 3.5V .
3.3.2 Recommended Operating Parameters
Table 4: Power Supply Operating Parameters
Parameter Minimum Typical Maximum Unit
VCC
1
1.8 3.3 3.5 V
VCC Maximum ripple or noise
2
10 mV
Operating Temperature Range -40 - +85 ºC
Note 1: Internal DCDC is used if VCC >2.1 V on power-up; otherwise internal LDO is used.
If supply voltage is greater than 3.5V, the LoRa transmitter will be disabled.