PXR40RM Datasheet, PDF (296/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Boot Assist Module (BAM)
9.5.6 Booting from the Development Bus
If the MCU boots in one of the Development Bus boot modes, the BAM program:
• Reprograms the MMU entries for EBI and internal flash (see Table 9-11)
• Sets up the EBI and development bus pins
• Tries to read RCHW from logical address 0x2000_0000
If the valid RCHW is read from that address, the BAM program:
• Reads the user application code start address from 0x2000_0004 address
• Parses RCHW
• Sets up watchdogs
• Updates EBI, SRAM and internal flash MMU entries(1-3), according to RCHW[VLE]
• Passes control to the user code
If no valid RCHW was read, BAM switches to the serial boot mode.
Table 9-11. MMU Configuration for Development Bus Boot modes
TLB
Entry
1
2
Region
Internal Flash
EBI
Logical
Base Address
0x0000_0000
Physical
Base Address
0x2000_0000
Size
16 MB
0x2000_0000 0x2000_0000
16 MB
Attributes
Not guarded
Big endian
Global PID
Not guarded
Big endian
Global PID
9.5.6.1 EBI Configuration for Separate Address and Data Development Bus
Boot Mode
The BAM program sets up EBI related registers as shown in the Table 9-12.
Table 9-12. Development Bus/EBI Register Settings for Separate Address Data lines mode
Register
Function
Value
Comments
EBI_CAL_BR0
EBI_CAL_OR0
SIU_PCR259–
SIU_PCR293
SIU_PCR305–
SIU_PCR307
SIU_PCR256
SIU_PCR295
SIU_PCR297
SIU_PCR298
—
—
D_ADD[12:30],
D_ADD_DAT[0:15]
D_ADD[9:11]
0x2000_0803
0xFF80_00F0
0x0440
Sets the base address to 0x2000_0000,16-bit wide
bus, burst Inhibit
Set 15 wait states, 8MB
Set pads to 20pf drive strength
D_CS0
D_WE0
D_OE
D_TS
0x443
Set pads to 20pf drive strength and pull-up enable
RCHW[PS0] must be programmed to “1”, since the development bus does not support 32-bit port size in
that sub-mode.
9-16
PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor