RM0046 Boot Assist Module (BAM)
Doc ID 16912 Rev 5 819/936
Figure 486. FlexCAN bit timing
33.6 FlexCAN boot mode download protocol
Table 442 summarizes the download protocol and BAM action during the FlexCAN boot
mode. All data are transmitted bytewise.
33.6.1 Autobaud feature
The autobaud feature allows boot operation with a wide range of baud rates independent of
the external oscillator frequency.
SYNC_SEG Time Segment 1 Time Segment 2
Sample Point
NRZ Signal
Transmit Point
1
time quanta time quanta time quanta
7 2
1 Bit Time
1 time Quanta = 4 system clock periods
Table 442. FlexCAN boot mode download protocol (autobaud disabled)
Protocol
step
Host sent
message
BAM response
message
Action
1
FlexCAN ID 0x011 +
64-bit password
FlexCAN ID 0x001 +
64-bit password
Password checked for validity and compared against
stored password.
2
FlexCAN ID 0x012 +
32-bit store address +
VLE bit+ 31-bit
number of bytes
FlexCAN ID 0x002 +
32-bit store address +
VLE bit + 31-bit
number of bytes
Load address is stored for future use.
Size of download is stored for future use.
Verify if VLE bit is set to 1.
3
FlexCAN ID 0x013 +
8 to 64 bits of raw
binary data
FlexCAN ID 0x003 + 8
to 64 bits of raw binary
data
8-bit data are packed into 32-bit words. These words
are saved into SRAM starting from the “Load address”.
“Load address” increments until the number of data
received and stored matches the size as specified in
the previous step.
4 none none Branch to downloaded code.
To Next Page
Loading...
