Laird Lyra S, User Manual

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Development board switch SW1 is used for selecting between two Software Development types, namely Bluetooth Xpress /
AT Commands or C Code Development, as described below. SW1 is used to determine the behaviour of the Development
board. Two possible switch positions are available as follows:
AT/BGx (Left-hand position) -
This position should be used when Silabs’ Bluetooth
Xpress or Laird Connectivity’s Lyra AT-Interface application is being evaluated.
Note: On development boards 2.2 and prior, AT/BGx is labelled BGx .
C-DEV (Right-hand Position)
– This position should be used when native C code
development, using the samples provided by Silabs Simplicity Studio is being performed.
Note: On development boards 2.2 and prior, C-DEV is labelled AT/SWO.
The default position for SW1 is the right-
hand position, ‘
C-DEV
’ (previously labeled AT/SWO).
Table 1: Recommended operating conditions
Parameter Symbol Min Typ Max Unit
USB Supply Input Voltage V
USB
- +5.0 - V
Supply Input Voltage (VMCU supplied externally)
V
VMCU
+3.3
1
V
Operating Temperature T
OP
- +20 -
˚C
1
The typical supply voltage to the Lyra S is 3.0 V, but the maximum voltage is a function of temperature and average lifetime
current load. Over a 10-year lifespan, the average lifetime current load should not exceed 60 mA when the supply voltage is
3.3 V. See the
Lyra S datasheet for more information.
The operating current of the board greatly depends on the application and the amount of external hardware connected. See
Table 2 for typical current consumptions for the Lyra S and the on-board debugger. Note that the numbers are taken from the
data sheets for the devices. For a full overview, see the Lyra S datasheet .
Table 2: Current consumption
Parameter Symbol Condition Typ Unit
Lyra S Current
Consumption
1
I
BGM
MCU current consumption in EM0 mode with all peripherals disabled
(module supply voltage = 3.0 V, VSCALE2, 38.4 MHz crystal, CPU
running Prime from flash at 25
˚C)
28 µA/MHz
Radio system current consumption in receive mode, active packet
reception (VDD = 3.0 V, MCU in EM1 and all MCU peripherals
disabled, HCLK = 38.4 MHz, 1Mbit/s, 2GFSK, f = 2.4 GHz at 25
˚C)
3.8 mA
Radio system current consumption in transmit mode (VDD
= 3.0 V, MCU in EM1 and all MCU peripherals disabled, HCLK = 38.4
MHz, f = 2.4 GHz, CW, 6 dBm output power at 25
˚C)
8.4 mA