NXP Semiconductors MPC5566 - Serial Boot Mode

Boot Assist Module (BAM)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 16-3
16.1.3.5 Serial Boot Mode
This mode of operation can load a user program into internal SRAM using either the eSCI or FlexCAN
serial interface, then execute the downloaded program. The program can then control the downloading of
data, as well as erasing and programming the internal or external flash memory.
Serial boot mode downloads:
• 64-bit password
• 32-bit start address
• 32-bit download consisting of 1-bit VLE flag (most significant bit)
followed by a 31-bit length field containing the number of bytes to receive (download length)
Set the VLE flag to 1 for devices that support variable length encoding and must run in VLE mode. When
the VLE flag is set, the BAM programs the external bus interface (EBI), RAM, and the flash memory map
unit (MMU) TLB entries 1, 2, and 3 with the VLE attribute.
Clear the VLE bit to 0 for devices that use the PowerPC Book E or Power Architecture instruction set
mode.
16.2 Memory Map
The BAM has 16 KB of memory, from 0xFFFF_C000 through 0xFFFF_FFFF, which is divided into four
4-KB segments, each containing a copy of the BAM program code. The BAM code resides in the 4-KB
memory segment beginning at 0xFFFF_F000. A copy of the BAM code resides in the three preceding
4-KB segment, as shown in Table 16-1. The BAM program executes from the reset vector at address
0xFFFF_FFFC.
Table 16-1 shows the addresses for the BAM code in the memory map.
16.3 Functional Description
16.3.1 BAM Program Resources
The BAM program initializes and uses the following MCU resources:
• BOOTCFG field in the reset status register (SIU_RSR) to determine the boot option
• Address and contents of the reset configuration halfword (RCHW), which contains the address and
configuration options for the boot code. Refer to Chapter 4, “Reset,” for information about the
RCHW.
Table 16-1. BAM Memory Map
Address Description
0xFFFF_C000–0xFFFF_CFFF BAM program mirrored
0xFFFF_D000–0xFFFF_DFFF BAM program mirrored
0xFFFF_E000–0xFFFF_EFFF BAM program mirrored
0xFFFF_F000–0xFFFF_FFFF BAM program