Texas Instruments TMS320DM355 warranty Power Management, Boot Mode Functional Block Diagram

TMS320DM355

Digital Media System-on-Chip (DMSoC)

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SPRS463A –SEPTEMBER 2007 –REVISED SEPTEMBER 2007

∙ARM ROM Boot - UART mode

–No support for a full firmware boot. Instead, loads a second stage user boot loader (UBL) via UART to ARM internal RAM (AIM) and transfers control to the user software.

–Support for up to 30KB UBL (32KB - ~2KB for RBL stack)

The general boot sequence is shown in Figure 3-6. For more information, refer to the ARM Subsystem User'sGuide.

		Reset
		Boot
		mode
		?			PREVIEW
Internal￿ROM			UART
		Boot
		mode
		?
Boot￿from			Boot￿from
NAND￿flash					PRODUCT
Boot￿OK￿?	No			No
			Boot￿OK￿?
Yes		Boot￿from	Yes
		MMC/SD
		No
		Boot￿OK￿?
		Yes
Invoke		Invoke￿loaded
OneNAND		Program

Figure 3-6. Boot Mode Functional Block Diagram

3.13 Power Management

The is designed for minimal power consumption. There are two components to power consumption: active power and leakage power. Active power is the power consumed to perform work and scales with clock frequency and the amount of computations being performed. Active power can be reduced by controlling the clocks in such a way as to either operate at a clock setting just high enough to complete the required operation in the required timeline or to run at a clock setting until the work is complete and then drastically cut the clocks (e.g. to PLL Bypass mode) until additional work must be performed. Leakage power is due

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