This section describes the global warm reset sequence.
Figure 3-37 shows the global warm reset sequence.
The assumptions are:
- All the logic and memory voltage sources are at their nominal voltage levels.
- The device is active:
- All resets are released.
- MPU, CORE, and IVA DPLLs are locked.
The steps of a global warm reset sequence are:
- On assertion of any global warm reset source the PRM signals the EMIF that a global warm reset event has occurred. The EMIF initiates the transition to IDLE state. The PRCM module delays global warm reset to the device for a minimum of 16 L3 clock cycles so that the EMIF switches to IDLE state and switches the external SDRAM to self-refresh mode.
- The reset managers in the PRM assert the following resets:
- The external warm reset SYS_WARM_RST (rstoutn pin).
- All power domain warm resets are asserted.
- The PRM and CM registers, sensitive to warm reset, are asynchronously reset.
- DPLL hardware resets are not asserted.
- DPLL_MPU transitions to bypass mode.
- DPLL_CORE transitions to bypass mode once the EMIF switches to IDLE state.
- DPLL_IVA, DPLL_PER, DPLL_USB, DPLL_DSP, DPLL_EVE, DPLL_GPU and DPLL_DDR transition to idle bypass low-power mode. Then, as clock signals are no more requested, they are gated and these DPLLs go to stop mode.
- DPLL_ABE configuration is not changed.
- DPLL_GMAC configuration is not changed.
- CM gates the clocks that are not needed, as per their default reset setting in the associated registers.
- The device warm reset (internal and rstoutn pin) duration is set up by the PRM_RSTTIME[9:0] RSTTIME1 bit field. It defines the global warm reset duration in number of FUNC_32K_CLK clock cycles. Default value loaded after POR is 6 clock cycles. During this time, the DPLL_ABE control registers are reset and DPLL_ABE transitions to bypass mode when the system clock restarts and the DPLL_ABE outputs are no longer used.
- The CORE power domain is released from reset (that is, warm reset-sensitive modules in the CORE power domain).
- The PRCM module switches the EMIF from IDLE state back to ACTIVE state.
- PD_MPU is released from reset when the clocks to the MPU subsystem are active. The MPU reboots.
Note: - The PD_DSP and PD_IVA, PD_EVE, PD_IPU2 power domains are held under reset after global warm reset by assertion of the software source of the reset.
- The following are held under reset after global warm reset until the PRCM module enables their interface clock:
- PD_L4PER
- PD_L3INIT
- PD_DSS
- PD_GPU
- PD_CAM