Software shutdown of PMIC not operational
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SPRUI64E – May 2017 – Revised September 2019
Copyright © 2017–2019, Texas Instruments Incorporated
Known Deficiencies in AM572x IDK EVM
A.8
Software shutdown of PMIC not operational
The PMIC is implemented to support PORz generation whenever any reset is initiated within the AM5728
SOC. This is enabled by pulling PMIC BOOT1 to VRTC. This has the side effect of requiring that PMIC
GPIO7/POWERHOLD also be pulled high. This results in an “always on” design that cannot be shut-off by
software. An external PORz pulse generator like that implemented on the X15 GP EVM would need to be
used to enable this feature. Please refer to i862 in the errata document for more information.
A.9
PMIC implementation does not support required SOC shut-down sequence
The AM5728 SOC requires that its supplies are sequenced on and off in the correct sequence to maintain
the reliability as stated in the
AM572x Sitara Processors Silicon Revision 2.0 Data Manual (SPRS982)
The PMIC can enforce this start-up and also the shut-down sequence if the PMIC RESET_IN is driven low
at least 1.1ms before the main supply to the PMIC collapses. However, the AM572x IDK EVM design
does not contain a circuit for this. Please refer to the AM571 IDK EVM design (v1.3 or later) for an
example of the required circuitry.
A.10
USB port providing UART console and XDS100 emulation not isolated from EVM
board supplies
Whenever the EVM power supplies are cycled, the USB connection supporting the UART console and
XDS100 emulation also drops. Since this port takes time to enumerate after power is restored, initial
console output can be lost. Also, this results in power leakage from the USB VBUS back into the EVM
when it is not powered. Please refer to the AM571 IDK EVM design (v1.3 or later) for an example of the
required circuitry that will allow the USB bridge to remain properly powered and isolated from the EVM to
prevent these negative affects.
A.11
Need 47-µf capacitor at camera header
Some camera video input instability has been seen. The solution for this is addition of a 47µF capacitor at
the supply pin for the camera header. This has been implemented on the AM571x IDK EVM v1.3 and
later.
A.12
Decoupling capacitors do not reflect AM572x PDN recommendations
Decoupling capacitors do not reflect AM572x PDN recommendations per
Simulations Application Report (SPRABY8)
These were corrected in the latest version of the AM571x IDK EVM. Please refer to the AM571 IDK EVM
design (v1.3 or later) for an example of the required circuitry.
A.13
CCS System Reset fails
Warm reset and emulation reset events configured for warm reset cause the Texas Instruments Code
Composer Studio™ (CCS) integrated development environment (IDE) to issue an error message. This is
due to the reset erratum that requires all resets to trigger a PORz low event. Since this is not expected by
CCS when it initiates a warm reset, it loses its context and issues an error. Newer versions of CCS handle
this event better but an error message will always be generated.
