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website and your local Motorola sales ofÞce for more information on the range of frequencies that the 603e
will operate at. The maximum frequency of operation under the full spec recommended temperature and
voltage ranges is encoded in the part number on the top of the part. This number might be 233MHz or
266MHz or 300MHz (always integer or half integer multiples of the 66MHz Excimer clock speed). The part
can be operated slower than this, to reduce power or for other reasons, as documented in the hardware
speciÞcation. While operation above the maximum frequency or below the minimum frequency for the
particular part is not recommended, the frequency can be changed via the PLL_CFG jumpers on the
Excimer board. If the PLL_CFG on Excimer is conÞgured for a frequency outside of the recommended
frequency range for the processor installed, program execution may fail or be unreliable.
The PLL_CFG jumper settings for Excimer are shown in Table 5.
WARNING: The PLL_CFG jumpers should never be changed while power is applied to the processor.
CAUTION : The microprocessor, linear regulator, and heat sink area of the board (See Figure 2) can get
very hot when the microprocessor is operated at high frequency (temperature at 300MHz is approximately
90¡C/195¡F) . When used for normal code development, 133MHz provides adequate performance and will
reduce the danger of injury (temperature approximately 66¡C/150¡F) if this area of the board is
inadvertently touched. If running above 133MHz, moving air from a nearby fan will assist in cooling the
components; a clip-on heatsink for the microprocessor will further reduce the microprocessorÕs temperature.
Jumper
Position
(seen as
pin1 pin2 pin3)
Vdd CFG
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
MOTOROLA
Table 5. Excimer Frequency (PLL_CFG jumper ) Settings
PLL_CFG[0Ð3]
0100
0101
0110
1000
1110
1010
0111
Minimal PowerPC 603e Evaluation Board
CPU Frequency in MHz (VCO
Frequency in MHz)
Bus-to-
Core-to
Core
VCO
Multiplier
Multiplier
2x
2x
2x
4x
2.5x
2x
3x
2x
3.5x
2x
4x
2x
4.5x
2x
Comment
Bus
66.67
MHz
133
Part may not work
here because of VCO
limitation.
133
Should work here
because VCO is 4x
the core frequency.
166
200
233
266
Check max processor
frequency
300
Check max processor
frequency
13
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