NEC IE-703242-G1-EM1, Preliminary User'S Manual

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Chapter 2 Name and Functions of Components
Preliminary User’s Manual U16345EE1V0UM00
2.5.2 Sub Clock
The V850ES/GB1 is available in different versions that feature different sub clock oscillators for device
operation at low frequencies:
• Crystal oscillator
• RC oscillator
If a crystal oscillator is used for the sub clock oscillator, a crystal of a fixed frequency of 32.768 KHz and
capacitors must be connected to the connector CN9.
For emulation of the RC oscillator a dedicated timer circuit on the emulation board can be used. This
timer circuit generates an adjustable frequency in the range of 40 to 100 KHz. If the timer circuit is used
the sub clock crystal and capacitors must be disconnected from CN9 and jumper JP1 must be shorted.
By default the timer circuit is configured to operate at a frequency of about 100 KHz. To adjust the
operating frequency of the sub clock timer circuit R28, R29 and C77 on the emulation board must be
changed.
Figure 2-5: Sub Clock Configuration
Caution: Since the clock inputs CL1 and CL2 (XT1 and XT2 respectively) are not connected to
the target, crystal or RC oscillator operation from the target board is not possible.
Crystal or RC oscillator provided on the emulation board must be used.
CL1
(XT1)
CL2
(XT2)
CN9
Venus
I/O chip
Oscillator
Circuit
JP1
32.768 KHz