SARA-R4 series - System Integration Manual
UBX-16029218 - R06
System description
Page 27 of 102
1.9.4
SDIO interface
The SDIO interface is not supported by “00”, “01” and “02” product versions: the SDIO interface pins
should not be driven by any external device.
SARA-R4 series modules include a 4-bit Secure Digital Input Output interface (
SDIO_D0
,
SDIO_D1
,
SDIO_D2
,
SDIO_D3
,
SDIO_CLK
,
SDIO_CMD
) designed to communicate with external compatible SDIO devices.
1.9.5
DDC (I
2
C) interface
The I
2
C interface is not supported by “00” and “01” product versions: the I
2
C interface pins should not be
driven by any external device.
SARA-R4 series modules include an I
2
C-bus compatible DDC interface (
SDA
,
SCL
) available to communicate with
a u-blox GNSS receiver and with external I
2
C devices as an audio codec: the SARA-R4 module acts as an I
2
C
master which can communicate with I
2
C slaves in accordance with the
I
2
C bus specifications
The
SDA
and
SCL
pins have internal pull-up to
V_INT
, so there is no need of additional components on the
external application board.
1.10
Audio
Audio is not supported by “00”, “01” and “02” product versions: the I
2
S interface pins should not be
driven by any external device.
SARA-R4 series modules support VoLTE (Voice over LTE Cat M1 radio bearer) for providing audio services.
SARA-R4 series modules include an I
2
S digital audio interface to transfer digital audio data to/from an external
compatible audio device.
The digital audio interface can be made available as alternative function, in mutually exclusive way, over the SPI
interface pins (
I2S_WA / SPI_MOSI
,
I2S_RXD / SPI_MISO
,
I2S_CLK / SPI_CLK
,
I2S_TXD / SPI_CS
).
