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PRCM Basic Programming Model
3.6.6.2
Reset Management
The reset sequence is hardware-driven. On power on, once all the reset sources have been released, the
PRM holds the entire device under reset long enough to ensure the stabilization of the power IC voltages
and the oscillator system clock frequency. This reset delay is programmed in the
register.
The IVA2.2 and the modem domain resets are held active after power up. They are released by writing to
the corresponding bits in the RM_RSTCTRL_<domain> register.
A domain reset status register (PRM_RSTST_domain>) identifies the source of the current reset applied
to the domain. The software must clear this status bit after reset.
A global reset status register (
) provides information about the global source of resets. All
sources of warm reset are logged separately in this register, and all sources of cold reset are logged in a
common status bit.
3.6.6.3
Wake-Up Control
The flow chart in
shows the control sequence of the module wake-up event.
This procedure consists of the following steps:
1. Program the PRCM module to consider the wake-up event.
2. Switch to idle mode and wait for the wake-up event.
3. Wake up on the wake-up event and activate the module functional clock.
4. Acknowledge the wake-up event.
The peripheral that can generate a wake-up event must be attached to a group of wake-up event
generating modules for one or both processors by programming the PM_<processor>GRPSEL register.
Writing 1 to this register allows the corresponding processor to be wakened on a peripheral wake-up
event, assuming that the peripheral wake-up capability has been enabled by programming the register
PM_WKEN_<domain>.
After this is configured, the PRCM module initiates a wake-up procedure on receiving the peripheral
wake-up event. The peripheral functional clock must be reenabled by programming the
CM_FCLKEN_<domain > register, and then the wake-up event can be acknowledged by clearing the
PM_WKST_<domain > register.
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SWPU177N – December 2009 – Revised November 2010
Power, Reset, and Clock Management
Copyright © 2009–2010, Texas Instruments Incorporated