12.1.4.6.1 Arm Exception Vectors Check

The ROM code reads and analyzes the first 28 bytes corresponding to the first seven Arm exception vectors of the bootstrap.

These exception vectors must implement either a branch or a load with PC-relative addressing Arm instructions, except for the 6th vector. Precisely, the ROM code must read either 0xEA or 0xE5 in bytes 3, 7, 11, 15 and 23.

The sixth vector (32 bits), at offset 0x14, must contain the size in bytes of the bootstrap to download from the external NVM into the internal SRAM.

The value must be lower than 32 Kbytes.

The following is an example of valid vectors:

					
00			ea000006					B 0x20
04			eafffffe					B 0x04
08			eafffffe					B 0x08
0c			eafffffe					B 0x0c
10			eafffffe					B 0x10
14			00001234					← Code size = 4660 bytes
18			eafffffe					B 0x18