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TMS320DM6437
Digital Media Processor
SPRS345B–NOVEMBER 2006–REVISED MARCH 2007
For proper device operation, external pullup/pulldown resistors may be required on these device boot and
configuration pins. For discussion situations where external pullup/pulldown resistors are required, see
Section 3.9.1
,
Pullup/Pulldown Resistors
.
Note:
except for PCIEN, all other DM6437 configuration inputs (BOOTMODE[3:0], FASTBOOT,
AEAW[2:0]/PLLMS[2:0] and AEM[2:0]) are multiplexed with other functional pins. These pins function as
device boot and configuration pins only during device reset. The user
must
take care of any potential data
contention in the system. To help avoid system data contention, the DM6437 puts these configuration pins
into a high-impedance state (Hi-Z) when device reset (RESET
or
POR) is asserted, and continues to hold
them in a high-impedance state until the internal global reset is removed; at which point, the default
peripheral (either GPIO
or
EMIFA based on default of AEM[2:0]) will now control these pins.
All of the device boot and configuration pin settings are captured in the corresponding bit fields in the
BOOTCFG register (see
Section 3.4.2.1
).
The following subsections provide more details on the device configurations determined at device reset:
AEM, AEAW/PLLMS, and PCIEN.
3.5.1.1
EMIFA Pinout Mode (AEM[2:0])
To support different usage scenarios, the DM6437 provides intricate pin multiplexing between the EMIFA
and other peripherals. The PINMUX0.AEM register bit field in the System Module determines the EMIFA
Pinout Mode. The AEM[2:0] pins only select the default EMIFA Pinout Mode. It is latched at device reset
de-assertion (high) into the BOOTCFG.DAEM bit field. The AEM[2:0] value also sets the default of the
PINMUX0.AEM bit field. While the BOOTCFG.DAEM bit field shows the actual latched value and
cannot
be modified, the PINMUX0.AEM value can be changed by software to modify the EMIFA Pinout Mode.
Note:
the AEM[2:0] value
does not
affect the operation of the EMIFA module itself. It
only
affects which
EMIFA pins are brought out to the device pins. For more details on the AEM settings, see
Section 3.7
,
Multiplexed Pin Configurations
.
In addition, for Fastboot modes (FASTBOOT = 1), the bootloader code determines the PLL1 multiplier
based on the default settings of AEM[2:0] and PLLMS[2:0]. For more details, see
Section 3.4.1.1
,
Fastboot
, and
Section 3.5.1.2
,
EMIFA Address Width Select (AEAW) and FASTBOOT PLL Multiplier
Select (PLLMS)
.
3.5.1.2
EMIFA Address Width Select (AEAW) and FASTBOOT PLL Multiplier Select (PLLMS)
The AEAW[2:0]/PLLMS[2:0] pins serve two functional purposes (AEAW
or
PLLMS), depending on the
FASTBOOT and AEM settings. The AEAW[2:0]/PLLMS[2:0] pins are latched at device reset de-assertion
(high) and captured in the BOOTCFG.PLLMS bit field. This value also sets the default of the
PINMUX0.AEAW field.
While the BOOTCFG.PLLMS field shows the actual latched value and
cannot
be modified, the
PINMUX0.AEAW value
can
be changed by software to modify the EMIFA pinout.
AEAW as EMIFA Address Width Select (AEAW)
If AEM[2:0] = 001b [8-bit EMIFA (Async) Pinout Mode 1], the AEAW[2:0]/PLLMS[2:0] pins serve as AEAW
to set the default of the EMIFA Address Width Selection.
When EMIFA is used in the 8-bit EMIFA (Async) Pinout Mode 1 (PINMUX0.AEM = 001b), the user has the
option to determine how many address pins are needed. The unused address pins can be used as
general-purpose input/output (GPIO) pins
or
extra data pins for VPFE. For more details on how the AEAW
settings control the exact pin out when AEM = 001b, see
Section 3.7.3.13
,
EMIFA/VPSS Block Muxing
.
For other EMIFA Pinout Modes (AEM not 001b), AEAW is
not
applicable in determining the EMIFA
address width.
Note:
AEAW[2:0] value
does not
affect the operation of the EMIFA module itself. It
only
affects which of
the EMIFA address bits are brought out to the device pins.
Device Configurations
96
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