Texas Instruments OMAP5910 Reference Manual page 232

DSP Subsystem Reset, Clocking, Idle Control, and Boot
12.4.3.2 External Memory Boot Mode
12.4.3.3 DSP Idle Boot Mode
12.4.3.4 Internal Memory Boot Mode
232 DSP Subsystem
When BOOT_MODE[3:0] = 0001b, the External Memory Boot mode is
selected. In this mode, the bootloader does execute. After initializing the
resources described in section 12.4.2.1, the bootloader simply branches to
byte address 0x08 0000 in DSP external memory.
Note:
The MPU core may need to set up the DSP MMU such that the DSP core
executes from valid DSP external memory.
When BOOT_MODE[3:0] = 0010b at reset, the DSP Idle Boot mode is
selected. In this mode, the bootloader will place the DSP subsystem into its idle
state using the following sequence:
Disable the DSP watchdog timer.
-
Set the DSP RAM and peripherals to shared-access mode (SAM) with the
-
HOM_R and HOM_P bits of ST3_55.
Set all the DSP domains to idle through the Idle Control Register (ICR).
-
Set the DSP RAM and peripherals to host-only mode (HOM) with the
-
HOM_R and HOM_P bits of ST3_55.
Execute the IDLE instruction.
-
A hardware or software reset can wake up the DSP subsystem from its idle
state.
In this mode, code and data sections must be initialized before the bootloader
is executed. Internal memory can be directly initialized by the MPU core or
system DMA via the MPUI port while the DSP core is in reset. When the DSP
subsystem is released from reset, the bootloader will branch to the byte
address specified by the selected boot mode.
The general procedure for an internal memory boot is:
The code and data sections are loaded into DSP subsystem internal
-
memory by the MPU core or system DMA via the MPUI port.
The MPU core takes the DSP subsystem out of reset with an internal
-
memory boot mode selected by the BOOT_MODE[3:0] bits.
The bootloader executes and transfers execution to the appropriate byte
-
address, and the loaded application begins running.
SPRU890A