
Yes
Yes
No
No
On POR or
Simulated POR
Does BOOTCFG.PORT.PIN.POL
match the actual port pin polarity and
BOOTCFG.EN = 0
Is flash data = 0xFFFFFFFF at
address 0x00000004?
Proceed to
application image
Proceed to
ROM bootloader
Functional Description
534
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Internal Memory
7.2.2.1
Boot Configuration
After POR and device initialization occurs, the hardware loads the stack pointer from flash or ROM based
on the presence of an application in flash and the state of the EN bit in the BOOTCFG register. If the flash
address 0x0000.0004 contains an erased word (value 0xFFFF.FFFF) or the EN bit is of the BOOTCFG
register is clear, the stack pointer and reset vector pointer are loaded from ROM at address 0x0100.0000
and 0x0100.0004, respectively. The bootloader executes and configures the available boot slave
interfaces and waits for an external memory to load its software. The bootloader uses a simple packet
interface to provide synchronous communication with the device. The speed of the bootloader is
determined by the internal oscillator (PIOSC) frequency. The following serial interfaces can be used:
•
UART0
•
SSI0
•
I2C0
•
USB
If the check of the flash at address 0x0000.0004 contains a valid reset vector value and the EN bit in the
BOOTCFG register is set, the stack pointer and reset vector values are fetched from the beginning of
flash. This application stack pointer and reset vector are loaded and the processor executes the
application directly. Otherwise, the stack pointer and reset vector values are fetched from the beginning of
ROM.
shows the bootloader selection sequence.
Figure 7-2. Boot Configuration Flow