Placing The Dsp Dma In Idle - Texas Instruments OMAP5910 Reference Manual

DSP Subsystem Reset, Clocking, Idle Control, and Boot

Placing the DSP DMA in Idle

Placing the Entire DSP Module Domain in Idle
224 DSP Subsystem
To set the DSP DMA domain to idle, follow these steps:
1) Set the DMA domain bit in the idle control register (ICR) by writing 0x0002
to ICR.
2) Use the DSP core to execute the IDLE instruction. The contents of ICR are
copied to the idle status register (ISTR). This places the DMA domain into
its idle state.
To wake up the DMA domain, follow these steps:
1) Clear the DMA domain bit in ICR by writing 0x0000 to ICR.
2) Use the DSP core to execute the IDLE instruction.
Note:
When the DMA domain is idle, there is one case when it can be temporarily
reactivated without a change in the idle configuration. If one of the
multichannel buffered serial ports (McBSPs) needs the DMA controller for
a data transfer, the DMA controller will leave its idle state to perform the data
transfer and then enter its idle state again.
To idle all the domains in the DSP module, follow these steps:
1) Set all the idle domain bits in the idle control register (ICR) by writing
0x0027 to ICR.
2) Use the DSP core to execute the IDLE instruction. The contents of ICR are
copied to the idle status register (ISTR). This places all the domains into
their idle states.
To wake up all the domains from this idle configuration, follow these steps:
1) Interrupt the DSP core using a maskable interrupt. The CPU and CPUIS
bits of ICR and ISTR, respectively, are automatically cleared. This takes
the CPU domain out of the idle state.
2) Clear all the idle domain bits in ICR by writing 0x0000 to ICR.
3) Use the DSP core to execute the IDLE instruction. This takes the rest of
the domains out of idle.
SPRU890A