Visible to Intel only — GUID: sfo1410069671347
Ixiasoft
Visible to Intel only — GUID: sfo1410069671347
Ixiasoft
20.4.5.3. Glue Logic for Master Port ss_in_n
When configured as a master, the SPI has an input, ssi_in_n, which can be used by the deciding logic in a multi-master system to disable one master when another has priority. 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 |