Flash Layout

This document summarizes the CC1352R flash/RAM placement used by Rehydrator and the boot order expected by TI BIM.

Memory Regions

Region	Address range	Use
Flash	0x00000000 - 0x00057FFF	Firmware images, OAD headers, BIM, and CCFG
SRAM	0x20000000 - 0x20013FFF	Runtime data, stack, BSS, and DMA tables
GPRAM	0x11000000 - 0x11001FFF	Cache/GPRAM area
ROM	Device internal	TI ROM boot code and helper routines

Firmware Slots

Slot	Start	End	Role
User image	0x00000000	0x0002FFFF	First APPSTACKLIB image checked by BIM
Persistent fallback	0x00030000	0x00051FFF	Fallback when the user image is missing or invalid
Metadata	0x00052000	0x00053FFF	Reserved update metadata area
Recovery	0x00054000	0x00055FFF	Reserved recovery/staging area
BIM + CCFG	0x00056000	0x00057FFF	TI BIM and critical device configuration

Each image reserves the first 0x100 bytes for the OAD image header. The reset vector table starts immediately after that header area.

Image	Header	Entry / reset vector	Image type
new-firmware	0x00000000	0x00000100	APPSTACKLIB
old-firmware	0x00030000	0x00030100	PERSISTENT_APP

Boot Order

flowchart TD
    A[Reset] --> B[ROM boot and CCFG settings]
    B --> C[TI BIM at 0x00056000]
    C --> D{Valid APPSTACKLIB at page 0?}
    D -- Yes --> E[new-firmware entry 0x00000100]
    D -- No --> F{Valid persistent fallback?}
    F -- Yes --> G[old-firmware entry 0x00030100]
    F -- No --> H[Boot failure or recovery path]

Loading

BIM checks the page 0 user image first. If only old-firmware is programmed, the user slot is empty and BIM falls back to the persistent image. After new-firmware is programmed at page 0, BIM selects it as long as its OAD header is valid.

CCFG Note

CCFG controls reset and boot behavior. In this layout CCFG is bundled with BIM inside the last flash sector:

0x00056000 - 0x00057FFF

Do not use full chip erase while testing this layout unless BIM + CCFG will be reprogrammed immediately afterwards.

Design Questions

Question	Answer
Where is the first working old image placed?	old-firmware is placed in the persistent fallback slot: 0x00030000 - 0x00051FFF.
Where is the update image placed?	new-firmware is placed in the page 0 user slot: 0x00000000 - 0x0002FFFF.
Can two complete images exist at the same time?	Yes for these small examples. The general answer depends on application size and the chosen OAD layout.
What if only a staging area exists?	A bootloader or recovery routine must verify and copy the staged image into an executable slot, or expose it through a BIM-compatible header.
Why avoid erasing the running image or BIM sector?	Flash erase is sector based. Erasing the active image, fallback image, BIM, or CCFG can break the boot flow.