Data Sheet

RM1xx LoRa/BLE Modules
Datasheet
https://connectivity.lairdtech.com/wireless-
modules/lorawan-solutions
14
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Note 1: Stay within internal 1.2 V reference voltage with given prescaling on AIN pin and do not violate ADC maximum
input voltage (for damage) for a given VCC, e.g. If VCC is 1.8 V can only expose AIN pin to 2.1 V (VCC+0.3).
Note 2: Currently, the smartBASIC runtime engine firmware only allows 10-bit mode.
Note 3: ADC input impedance is estimated mean impedance of the ADC (AIN) pins. The tolerance is +/-20%. The ADC is
highly sensitive to the impedance of the source. The ADC (AIN) input impedance is 200k-600k depending on
your ADC gain (pre-scaling) setting. Normally, when not sampling, the ADC (AIN) impedance will have very
high value and can consider it to be an open circuit. The moment ADC is sampling, ADC (AIN) impedance is
200k-600k.
3.3.3 nAutoRUN Pin and Operating Modes
Operating modes (refer to the smartBASIC manual for details):
 Self-contained mode
 Interactive/Development mode
Table 7: nAutoRUN pin
Signal Name Pin # I/O Comments
nAutoRUN (SIO_25) 6 I
Input with active low logic.
Operating mode selected by nAutoRun pin status:
If Low (0V), runs $autorun$ if it exists;
If High (VCC), runs via at+run (and “file name” of application).
Pin 40 (nAutoRUN) is an input, with active low logic. In the development board (DVK-RM1xx) it is connected so that the
state is driven by the host’s DTR output line. nAutoRUN pin needs to be externally held high or low to select between the
two RM1xx operating modes:
 Self-contained Run mode (nAutoRUN pin held at 0V).
 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 named $autorun$ then the smartBASIC runtime engine executes the application automatically;
hence the name self-contained run mode.
3.3.4 LoRa Output Power and Current Consumption vs Vcc
To maximize output power, the best choice for module Vcc is 3.3V +/- 5% (which results in a Vcc range of 3.14V to 3.47V).
The data in Table 8 was taken at 25ºC with UART on and all other peripherals turned off. It shows how the output power
and transmitter current consumption falls off as a function of Vcc.
Table 8: Power consumption and output power vs Vcc
RM186 RM191
Vcc
[V]
Tx Current
[mA]
Rx Current
[mA]
Pout
[dBm]
Tx Current
[mA]
Rx Current
[mA]
Pout
[dBm]
3.5 31.4 12.7 13.8 45.7 15.3 15.2
3.3 30.9 12.6 13.5 43.3 15.0 14.9
3.0 29.5 12.3 13.0 39.8 15.1 14.3
2.7 27.9 12.2 12.2 36.3 14.8 13.4