SWRU626 December 2025 CC3501E , CC3551E
The On-the-Fly Decryption Encryption (OTFDE) IP is primarily intended to support on-the-fly decryption of a code fetched from external serial Flash via Execute-In-Place (XIP) mode. The OTFDE is designed to provide system memory directly based on the fly encrypt/decrypt services. In addition, support for the bypass is provided.
At the Host-MCU level, the OTFDE IP is part of the access chain, along with the cache controller and xSPI controller IPs, for storing/fetching code and data to/from external memory devices; Flash and optionally PSRAM. The external memories are split into logical memory regions based on the device type, managed content (code/data) and the required security level (encrypted/plaintext). System consumers of the OTFDE services include the Instruction cache for fetching code hosted on the external serial flash and Data (SW) and µDMA for storing and retrieving data on an external serial flash and PSRAM.
OTFDE supports the following features: