ST SPC560P34 - Table 439. Fields of SSCM STATUS Register Used by BAM; Table 440. Serial Boot Mode Without Autobaud-Baud Rates

RM0046 Boot Assist Module (BAM)
Doc ID 16912 Rev 5 813/936
Then, the initial device configuration is restored and the code jumps to the address of
downloaded code. At this point BAM has just finished its task.
If an error occurs, (e.g., communication error, wrong boot selected, etc.), the BAM restores
the default configuration and puts the device into static mode. Static mode means the device
enters the low power mode SAFE and the processor executes a wait instruction. This is
needed if the device cannot boot in the selected mode. During BAM execution and after, the
mode reported by the field S_CURRENT_MODE of the register ME_GS in the module ME
Module is “DRUN”.
BAM resources
BAM uses/initializes the following MCU resources:
● ME and CGM modules to initialize mode and clock sources
● CAN_0, LINFlex_0, and their pads when performing serial boot mode
● SSCM to check the boot mode and during password check (see Tabl e 43 9 and
Figure 483)
● External oscillator
The following hardware resources are used only when autobaud feature is selected:
● STM to measure the baud rate
● CMU to measure the external clock frequency related to the internal RC clock source
● FMPLL to work with system clock near the maximum allowed frequency (this to have
higher resolution during baud rate measurement).
As already mentioned, the initial configuration is restored before executing the downloaded
code.
When the autobaud feature is disabled, the system clock is selected directly from the
external oscillator. Thus the oscillator frequency defines baud rates for serial interfaces used
to download the user application (see Table 440).
Table 439. Fields of SSCM STATUS register used by BAM
Field Description
BMODE
[2:0]
Device Boot Mode
000 Test Flash/autobaud_scan
001 CAN Serial Boot Loader
010 SCI Serial Boot Loader
011 Single Chip
100–111Reserved
This field is updated only during reset.
Table 440. Serial boot mode without autobaud—baud rates
Crystal frequency
(MHz)
LINFlex baud rate
(baud)
FlexCAN bit rate
(bit/s)
f
extal
f
extal
/ 833 f
extal
/ 40
8 9600 200 K
12 14400 300 K