Usage Notes and Known Design Exceptions to Functional Specifications
3.2
Known Design Exceptions to Functional Specifications
The following advisories are known design exceptions to functional specifications. Advisories are
numbered in the order in which they were added to this document. Some advisory numbers may be
moved to the next revision and others may have been removed because the design exception was fixed
or documented in the device-specific data manual or peripheral user's guide. When items are moved or
deleted, the remaining numbers remain the same and are not re-sequenced.
Advisory 1.0.1
DDR2, DDR3, mDDR PHY: Control and Status Registers Configured for Write Only
Revisions Affected
2.1, 2.0, 1.0
Details
The DDR2, DDR3, mDDR PHY control and status registers mapped in address range
0x44e12000-0x44E123FF are configured for write-only operations, so the contents of
these register cannot be read.
These registers must be configured by performing write-only operations.
Workarounds
There is no workaround for this issue.
Advisory 1.0.2
Debug Subsystem: EMU[4:2] Signals Are Not Available by Default After Reset
Revisions Affected
2.1, 2.0, 1.0
Details
All Debug subsystem components should remain unchanged when warm reset is
asserted. For example, warm reset should not affect export of debug trace messages on
the EMU[4:0] signals.
The AM335x EMU[4:2] signals can not be used to export trace messages from the
Debug subsystem since AM335x does support warm reset and the EMU[4:2] signals are
not assigned to pins after reset is asserted.
Workarounds
Do not assert warm reset while performing trace functions.
Advisory 1.0.3
Debug Subsystem: Internal Inputs Tied-off to the Wrong Value
Revisions Affected
2.1, 2.0, 1.0
Details
Internal inputs dbg_dpio_attr_dp_app_owner[4:0] and dbg_dpio_attr_dp_debug_only[4:0]
to the Debug subsystem are used to report which EMU[4:0] signals can currently be
used to export trace messages. These inputs were tied-off to the wrong value. The tie-off
values used always indicates EMU[4:2] signals are not available and EMU[1:0] signals
are available to export trace messages.
This should not cause a problem for EMU[4:2] since these signals can not be used to
export trace messages for the reason explained in advisory 1.3. However, the AM335x
pins used for EMU[1:0] signals may be configured as GPIO. The Debug subsystem
would not know these signals are not available for exporting trace messages when these
pins are configured as GPIO.
Workarounds
Do not configure the AM335x EMU[1:0] pins to operate as GPIO if you need to export
trace messages.
12
SPRZ360F – October 2011 – Revised November 2013
Sitara™ AM335x ARM
®
Cortex™-A8 Microprocessors (MPUs) (Silicon
Revision 2.1, 2.0, 1.0)
Copyright © 2011–2013, Texas Instruments Incorporated
