Getting started with the AEK-COM-ISOSPI1, SPI to isolated SPI dongle based on
introduction
One of the most commonly used communication protocols for device control is the SPI one. In the traditional vehicle
architecture, the SPI control is used to connect the device with the local microcontroller. With trends moving toward domain /
zone architectures, the local microcontroller is disappearing, therefore the protocol has to evolve to cover longer distances to
connect the device to the domain / zone controller. In addition, with electrification progressing inside the new vehicles, another
desirable feature for such a protocol is the electrical isolation. Based on these requirements, the isolated SPI (ISOSPI) protocol
has been defined.
The
AEK-COM-ISOSPI1
board allows converting SPI signals into ISOSPI signals, reducing the number of necessary wires from
4 to 2, and ensuring an isolated differential communication highly immune to noise.
An ISOSPI signal can travel for several meters, maintaining a high ratio between signal and noise.
The ISOSPI protocol features differential communication to ensure higher noise immunity and robustness for long distance
communication. As the ISOSPI signals can travel for several meters, this protocol is particularly suitable for automotive high
voltage applications where electrical isolation is required by the safety standards and the cable length can affect the
communication among devices located in distant parts of the vehicle.
The
AEK-COM-ISOSPI1
board is based on the
transceiver, which can transfer communication data incoming from a classical 4-wire based SPI interface to a 2-wire isolated
interface (and vice versa).
The L9963T hosted on the
AEK-COM-ISOSPI1
any protocol of 8-to-64-bit SPI frames. The SPI peripheral can work up to 10 MHz when configured as a slave. The SPI clock
frequency can be programmed (250 kHz, 1 MHz, 4 MHz, or 8 MHz) when the device is configured as a master.
UM3187 - Rev 1 - June 2023
For further information contact your local STMicroelectronics sales office.
Figure 1.
SPI to ISOSPI conversion block diagram
L9963T
integrated circuit, a general-purpose SPI to isolated SPI bi-directional
can be configured either as a slave or as a master of the SPI bus and supports
UM3187
User manual
the L9963T transceiver
www.st.com
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