Boot Assist Flash (Baf) - STMicroelectronics SPC572L series Reference Manual

RM0400
52

Boot Assist Flash (BAF)

52.1 Introduction
The MCU is booted through a collaboration of several blocks, hardware, and firmware. The
first boot phases are performed by a state machine inside the System Status and
Configuration Module (SSCM). Once completed, the SSCM sends a reset vector to the boot
core (Main Processor on this device) pointing into the Boot Assist Flash (BAF).
The BAF code then checks the life cycle of the device. If it is FAIL_ANALYSIS, the BAF
enters a loop in which it services the watchdog. The BAF does not execute further since the
read access to flash memory boot sectors for the core may be disabled if device life cycle is
FAIL_ANALYSIS. Otherwise, it searches for a boot header and boots the application code in
internal flash memory.
If no boot header is found in internal flash memory, it downloads application code serially
using the LINFlexD module. The package pins used by LINFlexD are the same pins used by
the M_CAN module. Hence, the external PHY can be either LIN or CAN, allowing the
"ASC@CAN" operation (see
details).
52.1.1 BAF image header
BAF image contains a 256-byte header starting from address 0040_4000h (BAF version
number, see the table "BAF memory map" in the "BAF Configuration"). The header contains
important information such as BAF version. The BAF header is explained in
Address offset
52.1.1.1 BAF image version
The BAF version is a 32-bit field in the image header starting at address 0040_4000h. The
32-bit field is explained in the following table.
Field
[0:7] Major Number: This field contains the major version number for the BAF image
[8:15] Minor Number: This field contains the minor version number for the BAF image
[16:23] Reserved
[24:31] Reserved
Section 52.2.6, Serial boot configuration
Table 873. BAF image header
0000h
0004h
0008h
000Ch
0010h–00FFh
Table 874. BAF image version
DocID027809 Rev 4
Size (bits)
32 BAF Image version
32 Reserved
Reserved (Part of clock Jitter
32
Activation Constant)
32 Clock Jitter Activation Constant
Reserved
Description
Boot Assist Flash (BAF)
for configuration
Table 873.
Field description
1543/2058
1559