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Boot Assist Module (BAM)
MPC5644A Microcontroller Reference Manual, Rev. 6
624
Freescale Semiconductor
The MMU regions are mapped with logical address the same as physical address except for the external
bus interface (EBI). The logical EBI address space is mapped to physical address space of the internal
Flash memory. This allows code, written to run from external memory, to be executed from internal Flash.
After the MMU configuration, the BAM program checks the BOOTCFG field of the reset status register
(SIU_RSR) and the appropriate boot sequence is started as shown in
.
Depending on the values stored in the censorship word and serial boot control word in the shadow row of
the internal Flash memory, the internal Flash memory can be enabled or disabled, the Nexus port can be
enabled or disabled, the password received in the serial boot mode is compared with the fixed public
password or compared to a user programmable password in the internal Flash memory.
Table 21-2. MMU configuration for internal flash boot
TLB
entry
Region
Logical
base address
Physical
base address
Size
Attributes
0
Peripheral Bridge B
1
and BAM
1
This device has only a single peripheral bridge, but to match the memory map of other devices in the MPC5500
family the peripherals are mapped to appear as if they are on two different peripheral bridges.
0xFFF0_0000
0xFFF0_0000
1 MB
Guarded
Big endian
Global PID
1
Internal Flash
0x0000_0000
0x0000_0000
16 MB
Not guarded
Big endian
Global PID
2
EBI
0x2000_0000
0x0000_0000
16 MB
Not guarded
Big endian
Global PID
3
Internal SRAM
0x4000_0000
0x4000_0000
256 KB
Not guarded
Big endian
Global PID
4
Peripheral Bridge A
0xC3F0_0000
0xC3F0_0000
1 MB
Guarded
Big endian
Global PID
Table 21-3. Boot modes
BOOTCFG
[0:1]
Censorship
control
0x00FF_FDE
0
Serial boot
control
0x00FF_FDE
2
Boot mode name
Internal
Flash
state
Nexus
state
Serial
password
00
!0x55AA
1
Any value
Internal—Censored
Enabled
Disable
d
Flash
0x55AA
Internal—Public
Enabled Enabled
Public
01
Any value
0x55AA
Serial—Flash password
Enabled
Disable
d
Flash
!0x55AA
Serial—Public password
Disable
d
Enabled
Public
Summary of Contents for MPC5644A
Page 2: ...MPC5644A Microcontroller Reference Manual Rev 6 2 Freescale Semiconductor...
Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
Page 26: ...MPC5644A Microcontroller Reference Manual Rev 6 26 Freescale Semiconductor...
Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
Page 1440: ...FlexCAN Module MPC5644A Microcontroller Reference Manual Rev 6 1440 Freescale Semiconductor...