Device Might Boot Into ROM Serial Bootloader When Waking Up From
Shutdown
Revisions Affected:
Revision C
Details:
For the conditions given below, the device will
boot into and execute the ROM serial bootloader
when waking up from Shutdown power mode. Intended
behavior is to execute the application image. The
prerequisites for this erratum to happen are:
- The wake up from Shutdown must be caused by toggling or noise on the JTAG TCK pin and
not by a GPIO event.
- The Customer Configuration Section (CCFG) must
have configured the bootloader with the following
field values:
- BOOTLOADER_ENABLE = 0xC5 (Bootloader
enabled)
- BL_ENABLE = 0xC5 (Bootloader pin backdoor
enabled)
- BL_PIN_NUMBER = n (any valid DIO number)
With the above prerequisites, the bootloader will
be entered in the following cases:
- The CCFG bootloader pin level (BL_LEVEL) is set
to 0x0 (active low) AND the input buffer enable
for the DIO defined in BL_PIN_NUMBER is disabled
in register IOC.IOCFGn.IE. If the input buffer is
not enabled, the DIO level will always read 0 and
bootloader will be entered.
- The input buffer controlled by IOC.IOCFGn.IE is
enabled and the DIO input value is the same level
as the CCFG bootloader pin level (BL_LEVEL) when
entering Shutdown (GPIO input values are latched
when entering Shutdown)
Please refer to the ICEMelter chapter in CC13x4x10, CC26x4x10 SimpleLink™ Wireless MCU TRM
for details on how noise entering the JTAG TCK pin can wake up the device
Workarounds:
One of the following workarounds must be
implemented:
- If input buffer is not enabled, use only active
high bootloader pin level (BL_LEVEL)
- If input buffer is enabled, ensure DIO input pin
level is not the same as bootloader pin level
(BL_LEVEL) when entering Shutdown.