ORSPI4 datasheet(5/263 Pages) LATTICE

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Lattice Semiconductor

ORCA ORSPI4 Data Sheet

Figure 2. System Model for SPI4 Interface

The details of the interface are speciﬁed in the OIF document “Implementation Agreement OIF-SPI4-02.0”

(www.oiforum.com). That speciﬁcation is based on the system model shown in the previous ﬁgure, which, in turn, is

based on the Open System Interconnect (OSI) reference model. In the system model, a “transmit interface” sends

address, start and end of packet signals and error control information from a Link Layer device to a PHY device and

receives ﬂow control (status) information from the PHY device. In the other direction, a “receive interface” at the

Link Layer receives data from a PHY device and sends status information to the PHY device. While this convention

provides a clear framework for deﬁning the system level functions, a clean separation between Link Layer and

Physical Layer functionality is not often seen in actual implementations.

The ORSPI4 FPSC SPI4 blocks implement the basic functions deﬁned in the standard and also implements addi-

tional options, as suggested in the standard, to conﬁgure parameters such as maximum burst size, calendar

length, length of training sequence, etc. As required by the speciﬁcation, the transmit and receive interfaces oper-

ate completely independently.

Receive Link

Layer Device

Physical (PHY)

Layer Device

TSTAT[1:0]

TSCLK

TDCLK

TDAT[15:0]

TCTL

RSTAT[1:0]

RSCLK

RDCLK

RDAT[15:0]

RCTL

PHY Layer in Model

Link Layer in Model

Transmit Link

Layer Device

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