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Evaluation Kit AT697F V3.0 [APPLICATION NOTE]
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Table 2-2 PROM code sizes
ROM bus width
EDAC
Code size
8 bits
Disabled
8 Mbits x1
– 8 Mbits available
8 bits (add a 5
th
bit for EDAC)
Enabled
8 Mbits x1
– 6.55 Mbits available
32 bits
Disabled
8 Mbits x2
– 16 Mbits available
40 bits (32 bits data + 8 bits EDAC)
Enabled
8 Mbits x3
– 16 Mbits available
IMPORTANT: until now, PROM8 is not recognized by GRMON.
The AT697 PROM bus width is configured at reset time according to PIO[1:0] value. Under reset the processor samples
PIO[1:0] and reports its value to the memory configuration register.
2.6.2.2 PROM40 Configuration (SW37.7 is OFF)
The 40-bit boot PROM is based on three M29W800D Flash memories (U19, U20 and U21). These chips are directly
soldered on the board. PROM 40 is implemented on the bottom side of the board as shows the following picture:
Figure 2-8. PROM40 implementation
In order to use the 40-bit mode, the following configuration shall be respected: SW37.7 is OFF.
2.6.2.3 PROM8 Configuration (SW37.7 is ON)
The 8-bit boot PROM is based on three M29W800D Flash memories (U22). The chip is directly soldered on the board.
PROM8 is implemented on the bottom side of the board close to the PROM40.
IMPORTANT:
when EDAC is activated with PROM8, memory available is less than without EDAC.