Clock Source; Operating Mode; Schematic Diagram Of The Clock Interface; Operating Mode Selection - Motorola 56F805 Hardware User Manual

2.4 Clock Source

The 56F805EVM uses an 8.00MHz crystal, Y1, connected to its External Crystal Inputs,
EXTAL and XTAL. The 56F805 uses its internal PLL to multiply the input frequency by
10 to achieve its 80MHz maximum operating frequency. An external oscillator source can
be connected to the hybrid controller by using the oscillator bypass connectors, JG6 and
JG18; see Figure 2-3.
Figure 2-3. Schematic Diagram of the Clock Interface

2.5 Operating Mode

The 56F805EVM provides a boot-up MODE selection jumper, JG7. This jumper is used
to select the operating mode of the device as it exits RESET. Refer to the
DSP56F801/803/805/807 User's Manual for a complete description of the chip's
operating modes.
Table 2-2
Operating Mode
0
3
2-6
Freescale Semiconductor, Inc.
EXTERNAL
OSCILLATOR
HEADERS
8.00MHz
shows the two operation modes available on the 56F805.
Table 2-2. Operating Mode Selection
JG7
1–2
No Jumper
56F805EVM Hardware User's Manual
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JG6 56F805
EXTAL
JG18
XTAL
Comment
Bootstrap from internal memory (GND)
Bootstrap from external memory (+3.3V)
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