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The AT command interface is not available on the I2C interface. The I2C device-mode operation is not
supported: the LENA-R8 series module can act as the I2C host that can communicate with I2C devices
in accordance with the I2C bus specifications [12].
1.11 Cellular audio interface
☞
LENA-R8001-00C and LENA-R8001M10-00C product versions do not support VoLTE.
LENA-R8 series cellular system includes a 4-wire digital audio interface (I2S_TXD data output,
I2S_RXD data input, I2S_CLK clock, I2S_WA world alignment / synchronization signal), available for
digital audio communication with external digital audio devices as an audio codec. Voice over LTE
(VoLTE) and Circuit-Switched Fall-Back (CSFB) services are employed through LTE or 2G radio bearer.
The I2S interface is configured in this way:
•
Normal I2S mode: long word alignment synchronization signal high / low with a 50% duty cycle
•
Local device role: bit clock and word alignment synchronization signal received as input from the
external audio device (as an audio codec)
•
Data with 16-bit word length, in 2's complement notation, linear, with MSB transmitted / read first
•
Word alignment synchronization signal frequency: 8 kHz, high for 16 bit clock cycles / low for 16
bit clock cycles, according to the data frame length
1.12 Cellular clock output
LENA-R8 series modules' cellular system provides digital clock output functionality on the GPIO6 pin.
This is mainly designed to feed the clock input of an external audio codec.
1.13 Cellular General Purpose Input/Output (GPIO)
LENA-R8 series modules include 5 pins (GPIO1-GPIO5) which can be configured as General Purpose
Input/Output or to provide custom functions via u-blox AT commands (for more details, see the u-blox
AT commands manual [2], +UGPIOC, +UGPIOR, +UGPIOW AT commands), as summarized in
Function
Network status
indication
GNSS supply enable
GNSS data ready
4
SIM card detection
General purpose input
General purpose output
Pin disabled
Table 7: LENA-R8 series GPIO custom functions configuration
1.14 Reserved pins (RSVD)
LENA-R8 series modules include pins reserved for future use, marked as RSVD, which can all be left
unconnected on the application board.
4
LENA-R8001 only
UBX-22015376 - R02
C1-Public
Description
Network status: registered home network, registered
roaming, data transmission, no service
Enable/disable the supply of the u-blox GNSS receiver
connected to the cellular system
Sense when the external u-blox GNSS system connected
to the cellular system is ready to send data by I2C
External SIM card physical presence detection
Input to sense high or low digital level
Output to set the high or the low digital level
Tri-state with an internal active pull-down enabled
System description
LENA-R8 series - System integration manual
Default GPIO
--
GPIO2
GPIO3
GPIO5
--
GPIO4
GPIO1
Table
7.
Configurable GPIOs
GPIO1, GPIO2,
GPIO3, GPIO4
GPIO1, GPIO2,
GPIO3, GPIO4
GPIO3
GPIO5
All
All
All
Page 29 of 116
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