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3.4.2
ARM Boot
3.4.3
DSP Boot
TMS320DM6446
Digital Media System on-Chip
SPRS283–DECEMBER 2005
The DM6446 ARM can boot from EMIFA, internal ROM (NAND) or UART as determined by the setting of
the BTSEL[1:0] pins. The BTSEL[1:0] pins are read by the ARM ROM Boot Loader (RBL) to further define
the ROM boot mode. The ARM boot modes are summarized in
Table 3-9
.
Table 3-9. ARM Boot Modes
BTSEL1
BTSEL0
Boot Mode
ARM Reset
Vector
0x0000 4000
Brief Description
0
0
ARM NAND RBL
Up to 14 K-bytes secondary boot loader through NAND with up
to 2 K-bytes page sizes.
EMIFA EM_CS2 external memory space.
Reserved
Up to 14 K-bytes secondary boot loader through UART.
0
1
1
1
0
1
ARM EMIFA External Boot
Reserved
ARM UART RBL
0x0200 0000
0x0000 4000
0x0000 4000
When the BTSEL[1:0] pins are set to the ARM EMIFA External Boot ("01"), the ARM immediately begins
executing code from the EMIFA EM_CS2 memory space (0x0200 0000). When the BTSEL[1:0] pins
indicate a condition other than the ARM EMIFA External Boot (!01), the RBL begins execution.
ARM NAND Boot mode has the following features:
No support for a full firmware boot. Instead, copies a secondary User Boot Loader (UBL) from NAND
flash to ARM Internal RAM (AIM) and transfers control to the user software.
Support for NAND with page sizes up to 2048 bytes.
Support for error correction when loading UBL
Support for up to 14KB UBL
Optional, user selectable, support for use of DMA, I-cache, and PLL enable while loading UBL
ARM UART Boot mode has the following features:
No support for a full firmware boot. Instead, loads a secondary UBL via UART to AIM and transfers
control to the user software.
Support for up to 14KB UBL
For further details on the ROM Bootloader, refer to the
ARM Subsystem Users Guide
.
For C64x+ booting, the state of the DSP_BT pin is sampled at reset. If DSP_BT is low, the MPU will be
the master of C64x+ and control booting (Host Boot mode). If DSP_BT is high, the C64x+ will boot itself
coming out of device reset (Self-Boot mode).
Table 3-10
shows a summary of the DSP boot modes.
Table 3-10. DSP Boot Modes
DSP_BT
DSP
Boot Mode
Host Boot
ARM
Boot Mode
Internal Boot
DSPBOOTADDR
Register Value
Programmable
Brief Description
0
ARM sets an internal DSP memory location in DSPBOOTADDR
register where valid DSP code resides and loads code to this
internal DSP memory through DMA prior to releasing DSP reset.
ARM sets an external DSP memory location in DSPBOOTADDR
register (EMIFA or DDR2) where valid DSP code resides prior to
releasing DSP reset.
Default EMIFA Base Address
0
Host Boot
External Boot
Programmable
1
Self Boot
Any
0x4220 0000
Device Configuration
63