Chapter 33 Boot Assist Module (BAM)
MPC5602P Microcontroller Reference Manual, Rev. 4
830
Freescale Semiconductor
Figure 33-8. FlexCAN bit timing
33.6
FlexCAN boot mode download protocol
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.
Table 33-9. FlexCAN boot mode download protocol (autobaud disabled)
Protoco
l
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.
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