Integration Manual
SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R13 System description Page 32 of 119
1.9.3 SPI interface
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The SPI interface is not supported by “00”, “01”, “02” and “52” product versions: the SPI interface pins should not be
driven by any external device.
SARA-R4/N4 series modules include a Serial Peripheral Interface for communication with compatible external device.
The SPI interface can be made available as alternative function, in mutually exclusive way, over the digital audio interface
pins (I2S_WA / SPI_MOSI, I2S_RXD / SPI_MISO, I2S_CLK / SPI_CLK,
I2S_TXD / SPI_CS).
1.9.4 SDIO interface
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The SDIO interface is not supported by “00”, “01”, “02” and “52” product versions: the SDIO interface pins should
not be driven by any external device.
SARA-R4/N4 series modules include a 4-bit Secure Digital Input Output interface (SDIO_D0, SDIO_D1, SDIO_D2, SDIO_D3,
SDIO_CLK, and SDIO_CMD) designed to communicate with external compatible SDIO devices.
1.9.5 DDC (I
2
C) interface
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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/N4 series modules include an I
2
C-bus compatible DDC interface (SDA, SCL lines) available to communicate with
a u-blox GNSS receiver and with external I
2
C devices as an audio codec: the SARA-R4/N4 series 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 [9].
The SDA and SCL pins have internal pull-up to V_INT, so there is no need of additional pull-up resistors on the external
application board.
1.10 Audio
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Audio is not supported by “00”, “01”, “02” and “52” ” product versions: the I
2
S interface pins should not be driven by
any external device.
SARA-R4/N4 series modules support VoLTE (Voice over LTE Cat M1 radio bearer) for providing audio services.
SARA-R4/N4 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).