ORSPI4 datasheet(13/263 Pages) LATTICE

13 / 263 page

Lattice Semiconductor

ORCA ORSPI4 Data Sheet

In addition to formatting received data and sending it to the FPGA logic, the receive block also sends status infor-

mation to the SPI4 status interface.

The Port Status Sequencer (PSS) block is responsible for providing port status to the SPI4 Receive Status block

logic according to a pre-conﬁgured calendar sequence. Status is derived from the ﬁll-levels of the DPRAM FIFOs

and/or from the FPGA status interface.

The SPI4 Receive Status block is responsible for FIFO status encoding, calendar management, status pattern

encoding (sync bits “11”), DIP-2 calculation and optional calendar selection word encoding.

The SPI4 Receive Status block contains the low speed LVTTL output buffers and LVDS output buffers necessary

for the output stage of receive status logic. The option to choose between LVTTL or LVDS outputs is done by set-

ting a control register bit.

SPI4 Debugging and Statistics Gathering Support

There are also several other features, including three loopback modes incorporated into the embedded core to

assist in debugging and statistic gathering. These features involve both the transmit and receive paths.

The three forms of loopback supported directly are:

• High-speed near-end loopback

• Far-end high-speed loopback

• Low-speed near-end loopback

The SPI4 blocks support the following error insertion and status reporting options for testing:

• DIP-4 odd parity is calculated over data and control words and inserted on the TX side. DIP-4 errors can be

forced by inverting the DIP-4 parity bits. DIP-4 parity is then checked at the receive interface.

• DIP-2 odd parity is calculated over the status frames and inserted on the RX side. DIP-2 errors can be forced by

inverting the DIP-2 parity bits. DIP-2 parity is then checked at the transmit status interface.

• Eight-bit counters are provided for counting DIP-4 and DIP-2 errors.

• Deskew error reporting for high-speed RX side dynamic alignment. This can cause an alarm.

• DPRAM FIFO overrun reporting. These can cause an alarm.

ORSPI4 Datenblatt(PDF) 13 Page - Lattice Semiconductor