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3.5
Configurations at Reset
3.5.1
Device Configuration at Device Reset
3.5.2
Peripheral Selection at Device Reset
TMS320DM6446
Digital Media System on-Chip
SPRS283–DECEMBER 2005
3.4.3.1
Host-Boot Mode
In host boot mode, the ARM is the master and controls the reset and boot of the C64x+. The C64x+ DSP
remains powered-off after device reset. The ARM is responsible for enabling power to the C64x+ and
releasing it from reset (PSC MMR bits: MDCTL[39].LRST and MRSTOUT1.MRSTz[39]). Prior to releasing
the C64x+ reset, the ARM must program the address from which the C64x+ will begin execution in the
DSPBOOTADDR register.
3.4.3.2
Self-Boot Mode
In self-boot mode, the C64x+ power domain is turned on and the C64x+ DSP is released from reset
without ARM intervention. The C64x+ begins execution from the default EMIFA address (0x4220 0000)
contained within the DSPBOOTADDR register. The C64x+ begins execution with instruction (L1P) cache
enabled.
The following sections give information on configuration settings for the device at reset.
Table 3-11
shows a summary of device inputs required for booting the ARM and DSP, and configuring
EMIFA data and address bus widths for proper operation of the device at the rising edge of the RESET
input.
Table 3-11. Device Configurations (Input Pins Sampled at Reset)
DEVICE SIGNALS
SAMPLED
AT RESET
BTSEL[1:0]
DEVICE SIGNAL NAME
AFTER RESET
DESCRIPTION
COUT[1:0]
ARM Boot mode selection pins.
‘00’ indicates ARM boots from ROM (NAND Flash).
‘01’ indicates that ARM boots from EMIFA (NOR Flash).
‘10’ Reserved.
‘11’ indicates that ARM boots from ROM (UART).
DSP Boot mode selection pin.
DSP_BT
COUT3
‘0’ sets ARM boot of C64x+.
‘1’ sets C64x+ self boot.
EMIFA data bus width selection pin.
EM_WIDTH
COUT2
‘0’ sets EMIFA to 8-bit data bus width
‘1’ sets EMIFA to 16-bit data bus width.
EMIFA address bus width selection pins for EMIFA address pins multiplexed with GPIO.
See
Table 3-12
,
Table 3-13
, and
Table 3-14
for details.
AEAW[4:0]
YOUT[4:0]
As briefly mentioned in
Table 3-11
, the state of the AEAW[4:0] pins captured at reset configures the
number of EMIFA address pins required for device boot. These values are stored in the AEAW field of the
PINMUX0 register. At reset, this provides proper addressing for external boot. Unused address pins are
available for use as GPIO. The register settings are software programmable after reset.
Table 3-12
,
Table 3-13
, and
Table 3-14
show the AEAW[4:0] bit settings and the corresponding multiplexing for
EMIFA address and GPIO pins.
The number of EMIFA address bits enabled is configurable from 0 to 23. EM_BA[1] and EM_A[21:0] pins
that are not assigned to another peripheral and not enabled as address signals become GPIO pins. The
enabled address pins are always contiguous from EM_BA[1] upwards and address bits cannot be skipped.
64
Device Configuration