Device might boot into ROM serial bootloader when waking up from shutdown
Revisions Affected:
Revision C and earlier
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 the CC13x1x3, CC26x1x3 SimpleLink™ Wireless MCU Technical Reference
Manual 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.