5 System Controller Suspend Mode

The PolarFire family of devices has a System Controller Suspend mode feature that can be used to force the System Controller into reset after device initialization is complete. This mode is essential for safety-critical applications to protect the device from unintended device programming or zeroization of the device due to Single Event Upset (SEU) events.

When using the System Controller Suspend mode feature, ensure to instantiate and configure the required PF_INIT_MONITOR or PFSOC_INIT_MONITOR IP cores with the Latch System Controller outputs feature enabled. When using the System Controller Suspend mode feature, all system controller outputs to the FPGA fabric are set to "0." Therefore, it is important to configure the PF_INIT_MONITOR or PFSOC_INIT_MONITOR IP cores to latch the system controller outputs during the System Controller Suspend mode, especially if the output signals are used to derive a Reset signal for the user logic. Further, the exposed CLK_160_MHZ port must be connected to the internal 160 MHz RCOSC.

When the System Controller Suspend mode is exited, the latches used by the PF_INIT_MONITOR or PFSOC_INIT_MONITOR IP cores are cleared, causing any active-low fabric resets, derived from output signals such as DEVICE_INIT_DONE, to be asserted.

Enabling the System Controller Suspend mode feature has some impact on device behavior as described in the following sections.