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12.5.2 DSP Module Clock ON/OFF
12.5.2.1 DSP Module Clock On
www.ti.com ARM Control of DSP Boot, Clock, and Reset
In the clock enable state, the DSP’s module clock is enabled while the DSP module reset is deasserted.
This is the state for normal DSP run-time.
• ARM: Enable clocks to the DSP:
1. Wait for the GOSTAT[0] bit in the power domain transition status register (PTSTAT) in the PSC to
clear to 0. You must wait for the power domain to finish any previously initiated transitions before
initiating a new transition.
2. Set the NEXT bit in the module control 1 register (MDCTL1) in the PSC to 3h to prepare the DSP
module for an enable transition.
3. Set the GO[0] bit in the power domain transition command register (PTCMD) in the PSC to 1 to
initiate the state transition.
4. Wait for the GOSTAT[0] bit in PTSTAT to clear to 0. The domain is only safely in the new state
after the GOSTAT[0] bit is cleared to 0.
5. Wait for the STATE bit in the module status 1 register (MDSTAT1) in the PSC to change to 3h. The
module is only safely in the new state after the STATE bit in MDSTAT1 changes to reflect the new
state.
6. Clocks are enabled to the DSP.
• ARM: Wake the DSP. If transitioning from the disable or idle state, trigger a DSP interrupt that has
previously been configured as a wake-up interrupt, (for example, set the INTDSP n or INTNMI bit in the
DSP interrupt set register (DSPINTSET) in the System Module.
Note: This step only applies if you are transitioning from the disable state. If previously in the
disable state, a wake-up interrupt must be triggered in order to wake the DSP. This example
assumes that the DSP enabled this interrupt before entering its IDLE state. If previously in
the software reset disable or synchronous reset state, it is not necessary to wake the DSP
because these states assert the DSP module reset. See Chapter 10 for information on the
software reset disable and synchronous reset states. See the TMS320C64x+ DSP
Megamodule Reference Guide (SPRU871 ) for more information on DSP interrupts.
SPRUEP9A – May 2008 ARM-DSP Integration 129
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