Intel® Stratix® 10 SoC FPGA Boot User Guide

ID 683847
Date 7/26/2022
Public

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Document Table of Contents

7.1. Reset

Table 16.  Reset Effects on Booting and Configuration
Reset Type Initiated By Details
Power-on Reset An external event
  • The entire HPS and FPGA are reset.
  • When the device is released from POR, SDM begins initialization. A POR is the only way initialization can begin.
  • POR is the only way to recover from a tamper event.
nCONFIG Reset nCONFIG pin An SoC device-wide reset input that cold resets the HPS and reconfigures the FPGA.
Cold Reset
  • SDM
  • HPS_COLD_nRESET pin
  • Watchdog Timeout Event (calls SDM)
  • All of HPS, except the HPS I/O, Clock Manager, Reset Manager, and the TAP controller, are reset.
  • An HPS cold reset does not impact the FPGA core and FPGA I/O (the device is not reconfigured).
  • The SDM reloads the FSBL into on-chip RAM.
  • When the HPS_COLD_nRESET pin asserts, the SDM begins the reset sequence.
Cold and Trigger Remote Update Reset Watchdog Timeout Event (calls SDM)
  • SDM requests reset manager to assert or de-assert cold reset.
  • When the HPS_COLD_nRESET pin asserts, the SDM begins the reset sequence.
  • The SDM loads the FSBL from the next bitstream or factory bitstream into on-chip RAM.
  • The FPGA is first erased and then loaded with an image from the next bitstream or factory bitstream. There must always be a factory image present.
Warm Reset
  • FSBL or any software that makes a warm reset request through the EL3 register4 software write to the RMR_EL3 register to trigger a warm reset to the CPUs. You can still use debug tools after a warm reset because it does not reset the debug modules. The SDM does not reload the FSBL on a warm reset. You must ensure that your FSBL can support reentry, or that your on-chip RAM contains the FSBL or minimum required to boot the system.
  • Watchdog Timeout Event (calls SDM)
  • Before you can write to the RMR_EL3 register, CPU0 must ensure that the other CPUs are in WFI mode. Immediately after the RMR_EL3 register is written, the WFI instruction must be executed.
  • All of the HPS, except debug, MPU debug, and the boot scratch registers in the System Manager are reset.
  • A warm reset does not reload the FSBL into the HPS. The FSBL remains in the on-chip RAM during a warm reset.
  • Warm reset of the HPS does not impact the FPGA core and I/O (the device is not reconfigured).
  • In the case of a single configuration and boot source, warm reset returns flash control from HPS to SDM.
Software Reset A software write to the Reset Manager
  • A software reset of a CPU does not affect SDM functionality.
Watchdog Reset Timeout from a user configurable watchdog timer register.
  • Each CPU has a dedicated watchdog timer.
  • L4 Watchdog Timer 0 is configured during HPS initialization.
  • Use the Intel® Quartus® Prime Pro Edition to configure the watchdog reset for an HPS cold, HPS warm, or HPS cold and trigger remote update reset. See other entries in this table for details on each reset type.
Debug Reset JTAG SRST pin
  • To control reset, you must connect the HPS_COLD_nRESET pin to the JTAG SRST pin.
  • A debug reset initiates a cold reset.
JTAG Reset JTAG SRST pin
  • JTAG can reset the entire device regardless of the MSEL[2:0] settings and reload a new configuration or test through JTAG.
Note: REBOOT_HPS triggers the HPS cold reset. Firmware loads the new bitstream from the boot source based on MSEL settings. The loaded bitstream and your device must use the same firmware version. When loading the new bitstream, SDM wipes HPS and loads the HPS bootloader to HPS OCRAM and releases MPU. For more information about HPS reset, refer to Intel® Stratix® 10 Hard Processor System Technical Reference Manual.

When the device is reset in secure mode, all system warm and watchdog resets are treated as a POR reset. When the HPS is released from reset, all CPUs begin executing the FSBL. The FSBL ensures that CPUs 1 through 3 are in wait-for-interrupt (WFI) mode.

4 The Cortex* -A53 has four levels of exception from EL3 to EL0. EL3 is the highest privilege and EL0 is the lowest.

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