Data Sheet

Table Of Contents
SARA-R4/N4 series - Data Sheet
UBX-16024152 - R16 Interfaces Page 13 of 39
The USB_D+ / USB_D- lines carry the USB data and signaling, while the VUSB_DET pin represents the
input to enable the USB interface by applying an external valid USB VBUS voltage (5.0 V typical).
The USB interface is available as an AT command / data communication interface only if an
external valid USB VBUS voltage (5.0 V typical) is applied at the VUSB_DET input of the module
since the switch-on of the module, and then held during normal operations. In this case, the UART
will not be available.
If the USB interface is enabled, the module does not enter the low power deep sleep mode: the
external USB VBUS voltage needs to be removed from the VUSB_DET input of the module to let it
enter the Power Saving Mode defined in 3GPP Rel.13.
SARA-R4/N4 series modules provide by default a set of two USB functions:
AT commands and data communication
Diagnostic log
For more details regarding USB configurations / capabilities, see the SARA-R4/N4 series System
Integration Manual [2].
2.5.3 SPI interface
The SPI interface is not supported by the “00”, “01”, “02” and “52” product versions.
SARA-R4/N4 series modules include a Serial Peripheral Interface for communications with compatible
external device.
The SPI interface can be made available as an alternative function, in a 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).
2.5.4 SDIO interface
The SDIO interface is not supported by the “00”, “01”, “02” and “52” product versions.
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.
2.5.5 DDC (I
2
C) interface
The DDC (I
2
C) interface is not supported by the “00” and “01” product versions.
SARA-R4/N4 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 for example an audio codec:
the SARA-R4/N4 series module acts as an I
2
C master that can communicate with I
2
C slaves in
accordance with the I
2
C bus specifications [11].
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.