Intel® Agilex™ Hard Processor System Technical Reference Manual

ID 683567
Date 2/14/2023
Public

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19.4.5.3. Glue Logic for Master Port ss_in_n

When configured as a master, the SPI has an input, ssi_in_n. The polarity of this signal depends on the serial protocol in use, and the protocol is dynamically selectable.

The table below lists the three protocols and the effect of ss_in_n on the ability of the master to transfer data. Note that for the SSP protocol the effect of ss_in_n is inverted with respect to the other protocols.

Protocol ss_in_n value Effect on Serial Transfer
Motorola SPI 1 Enabled
0 Disabled
National Semiconductor Microwire 1 Enabled
0 Disabled
Texas Instruments Serial Protocol (SSP) 1 Disabled
0 Enabled
Figure 87. SPI Configured as Master Device