Evaluation Board Manual
Preliminary
PPC750FX Evaluation Board
750FXebm_ch2.fm
June 10, 2003
Board Design
Page 23 of 115
The 8-bit wide Flash is installed at the top of the address space. Immediately below that Flash in the address
space is the SRAM. Switch #7 on switch U24 allows the exchange of the two blocks in the address space.
The intent of this SRAM is to aid in the debug of ROM boot code, not for speed enhancement. Flash contents
will be copied to SRAM, then SRAM will be placed at the top of the address space. ROM code can then be
debugged from SRAM, allowing the placement of unlimited software break points.
Note 1: A jumper at J8 can be installed to prevent any 32-bit Flash write operations.
Note 2: Caching the 8- or 32-bit Flash memories is not supported.
Table 2-2 and Table 2-3 describe the switch settings and the resulting configurations.
Table 2-2. Switch Settings
Configuration
U17 SW6
U24 SW 7
Description
1
ON
ON
8-bit boot, Flash at higher address
2
ON
OFF
8-bit boot, SRAM at higher address
3
OFF
ON
32-bit boot, Flash at higher address
4
OFF
OFF
32-bit boot, SRAM at higher address
Table 2-3. Flash Configurations
Configuration
Address Range
Module(s) selected
1
0xFFF00000 to 0xFFFFFFFF
8-bit Flash controlled by BootCS
0xFFE00000 to 0xFFEFFFFF
8-bit SRAM controlled by BootCS
0xFC000000 to 0xFDFFFFFF
32-bit Flash controlled by DevCS0
2
0xFFF00000 to 0xFFFFFFFF
8-bit SRAM controlled by BootCS
0xFFE00000 to 0xFFEFFFFF
8-bit Flash controlled by BootCS
0xFC000000 to 0xFDFFFFFF
32-bit Flash controlled by DevCS0
3
0xFE000000 to 0xFFFFFFFF
32-bit Flash controlled by BootCS
0xFC100000 to 0xFC1FFFFF
8-bit Flash controlled by DevCS0
0xFC000000 to 0xFC0FFFFF
8-bit SRAM controlled by DevCS0.
Note: In configuration 3, SRAM is at the beginning of the DevCS0 memory
range followed by 8-bit wide Flash.
4
0xFE000000 to 0xFFFFFFFF
32-bit Flash controlled by BootCS
0xFC100000 to 0xFC1FFFFF
8-bit SRAM controlled by DevCS0
0xFC000000 to 0xFC0FFFFF
8-bit Flash controlled by DevCS0.
Note: In configuration 4, 8-bit wide Flash is at the beginning of the DevCS0
memory range followed by SRAM.
Notes: 1.
The reset vector of the PPC750FX is 0xFFF00100.
2.
The base addresses of peripherals attached to the MV64360 system controller device are software dependent. The values
in the table above are used by the PPC750FX Evaluation Kit Software. Other software environments may use different
values for the peripheral base addresses.
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