Boot Assist Module (BAM)MPC5606S Microcontroller Reference Manual, Rev. 7176 Freescale Semiconductor6.5.5 Boot from UART6.5.5.1 ConfigurationBoot from UART protocol is implemented by the LINFlex 0 module. The pins used are:• LINFlex_TX—corresponds to pin PB[2]• LINFlex_RX—corresponds to pin PB[3]The system clock is driven by an external oscillator.The LINFlex controller is configured to operate at a baud rate = system clock frequency/833 (see Table 6-6for baud rate example), using an 8-bit data frame without parity bit and 1 stop bit.Figure 6-7. LINFlex bit timing in UART mode6.5.5.2 ProtocolTable 6-7 summarizes the protocol and BAM action during this boot mode.Table 6-7. UART Boot mode download protocol (autobaud disabled)ProtocolstepHost sentmessageBAM responsemessage Action1 64-bit password(MSB first)64-bit password Password checked for validity and compared against storedpassword.2 32-bit store address 32-bit store address Load address is stored for future use.3 VLE bit +31-bit number ofbytes (MSB first)VLE bit +31-bit number ofbytes (MSB first)Size of download is stored for future use.Verify if VLE bit is set to 1.4 8 bits of raw binarydata8 bits of raw binarydata8-bit data are packed into 32-bit words. This word is saved inSRAM starting from the “Load address”.“Load address” increments until the amount of data receivedand stored matches the size as specified in the previous step.5 None None Branch to downloaded code.
