LC87F1JJ8B Datasheet, PDF (24/28 Pages) Sanyo Semicon Device – 8-bit 1-chip Microcontroller with USB-host controller

LC87F1JJ8B
Subsystem Clock Oscillation
Table 1 shows the characteristics of a sample subsystem clock oscillation circuit that are measured using a SANYO-
designated oscillation characteristics evaluation board and external components with circuit constant values with which
the oscillator vendor confirmed normal and stable oscillation.
Table 1 Characteristics of a Sample subsystem Clock Oscillator Circuit with a Crystal Oscillator
Nominal
Frequency
Vendor Name
Oscillation
Circuit Constant
Operating
Oscillator
Stabilization Time
Voltage Range
Name
C3
C4
Rf
Rd2
typ
max
[V]
[pF]
[pF]
[Ω]
[Ω]
[s]
[s]
32.768kHz EPSON TOYOCOM MC-306
18
18
OPEN 560k
2.7 to 5.0
1.1
3.0
Remarks
Applicable CL
value=12.5pF
SMD type
The oscillation stabilization time refers to the time interval that is required for the oscillation to get stabilized in the
following cases (see Figure 4):
• Till the oscillation gets stabilized after the instruction for starting the subclock oscillation circuit is executed.
• Till the oscillation gets stabilized after the HOLD mode is released with EXTOSC (OCR register, bit 6) set to 1.
Note: The components that are involved in oscillation should be placed as close to the IC and to one another as possible
because they are vulnerable to the influences of the circuit pattern.
CF1
CF2
Rd1
C1
CF
C2
Figure 1 CF Oscillator Circuit
XT1
Rf
XT2
Rd2
C3
X’tal
C4
Figure 2 Crystal Oscillator Circuit
0.5VDD
Figure 3 AC Timing Measurement Point
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