MSS I/Os

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There are 38 general purpose I/O pads called as MSS I/Os, to support the peripherals listed in Table 1. System registers select the signals connected to the I/O pads. The MSS I/Os are in addition to the SGMII I/O for the Ethernet MACs, two I/Os for an external reference clock source, and DDR I/Os. All of these I/Os and MSS I/Os are bonded out to pins in all PolarFire SoC packages. The MSS I/Os can be configured as the I/Os of any of the following MSS peripherals using MSS I/O Bank 2 and Bank 4:

Due to the limited number of MSS I/Os, only certain combinations of these peripherals are simultaneously available. The USB, eMMC, and SD/SDIO are fixed peripherals. They are only mapped to one possible set of MSS I/O and cannot connect to the fabric I/O. The other peripherals are mapped to multiple MSS I/Os, through an I/O MUX block (see Figure 1). The peripherals that do not have a connection available to MSS I/Os in a given configuration, can be connected to fabric I/Os through the I/O MUX to fabric.

There are two voltage banks within MSSIO. This allows interfacing to different voltage standard components external to the device.

Important: The I/Os of MSS peripherals can be grouped across MSS I/O Bank 2 and Bank 4, if both Banks are configured to the same I/O standard. The following rules apply while selecting I/Os of MSS peripherals: