Visible to Intel only — GUID: sfo1410067638954
Ixiasoft
Visible to Intel only — GUID: sfo1410067638954
Ixiasoft
4. Reset Manager
The reset manager generates module reset signals based on reset requests from the various sources in the HPS and FPGA fabric, and software writing to the module-reset control registers. The reset manager ensures that a reset request from the FPGA fabric can occur only after the FPGA portion of the system-on-a-chip (SoC) device is configured.
The HPS contains multiple reset domains. Each reset domain can be reset independently. A reset may be initiated externally, internally or through software.
The Reset domains and sequences include security features. The security manager works with Power On Reset (POR) and brings the reset manager out of reset only when the secure fuses have been loaded and validated. Once this process is complete, the reset manager brings the rest of the HPS out of reset.
Domain Name |
Domain Logic |
Module Master |
Description |
---|---|---|---|
POR |
Power on Reset. The entire HPS is reset. |
Security Manager |
After POR, the security manager comes out of reset and validates the security fuses. After validation, the reset manager is released from reset and proceeds to perform a cold reset on the HPS. |
System Cold |
Cold Reset. All of the HPS except security manager and POR fuse logic. |
Reset Manager |
Using the known security state, the HPS is placed in the default state, allowing software to boot. Cold reset is triggered by POR as well as other sources. |
System Warm |
System Warm (SW) is a warm reset. All of the HPS except security manager, POR, Fuse Logic, and test access port (TAP), and Debug domains are reset. |
Reset Manager |
Used to recover system from a non-responsive condition. Resets a subset of the HPS state reset by a cold reset. Only affects the system reset domain, which allows debugging (including trace) to operate through the warm reset. It is possible to mask a warm reset for some modules such that they are not affected. |
Debug |
All debug logic including most of the DAP, CoreSight* ™ components connected to the debug peripheral bus, trace, the microprocessor unit (MPU) subsystem, and the FPGA fabric. |
Reset Manager |
May be asserted by cold reset, the debugger or software. Used to recover debug logic from a non-responsive condition. |
TAP |
JTAG test access port (TAP) controller, which is used by the debug access port (DAP). |
Reset Manager |
Asserted by cold reset or by Software. |
RAM Clear |
The on-chip memories are cleared |
Reset Manager |
Memories may be cleared on cold or warm as indicated by the corresponding bits in the ramstat register. |
The HPS supports the following reset types:
- System cold reset
- Used to ensure the HPS is placed in a default state sufficient for software to boot
- Triggered by a power-on reset and other sources
- Resets all HPS logic that can be reset
- Affects all reset domains
- System warm reset
- Used to recover system from a non-responsive condition
- Does not reset the Debug or TAP reset domain, allowing debug functions including trace to operate through out a warm reset
- Masks allow software to exclude modules from warm reset. Exceptions for masks:
- To maintain security, there is no mask for security manager
- The MPU cannot be masked
- RAM Clearing domain (if not masked) logic is reset
- Debug reset
- Used to recover debug logic from a non-responsive condition
- Only affects the debug reset domain
- TAP Reset
- JTAG TAP controller is reset
- Software may trigger TAP reset