C8051F060DK Silicon Laboratories Inc, C8051F060DK Datasheet - Page 175

DEV KIT FOR F060/F062/F063

C8051F060DK

Manufacturer Part Number
C8051F060DK
Description
DEV KIT FOR F060/F062/F063
Manufacturer
Silicon Laboratories Inc
Type
MCUr
Datasheet

Specifications of C8051F060DK

Contents
Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
Processor To Be Evaluated
C8051F06x
Interface Type
USB
Silicon Manufacturer
Silicon Labs
Core Architecture
8051
Silicon Core Number
C8051F060
Silicon Family Name
C8051F06x
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
For Use With/related Products
C8051060, C8051F062 and C8051F063
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
Other names
336-1214

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
C8051F060DK
Manufacturer:
Silicon Labs
Quantity:
135
15.4. External Crystal Example
If a crystal or ceramic resonator is used as an external oscillator source for the MCU, the circuit should be
configured as shown in Figure 15.1, Option 1. The External Oscillator Frequency Control value (XFCN)
should be chosen from the Crystal column of the table in Figure 15.5 (OSCXCN register). For example, an
11.0592 MHz crystal requires an XFCN setting of 111b.
When the crystal oscillator is enabled, the oscillator amplitude detection circuit requires a settle time to
achieve proper bias. Introducing a blanking interval of at least 1 ms between enabling the oscillator and
checking the XTLVLD bit will prevent a premature switch to the external oscillator as the system clock.
Switching to the external oscillator before the crystal oscillator has stabilized can result in unpredictable
behavior. The recommended procedure is:
Important Note on External Crystals: Crystal oscillator circuits are quite sensitive to PCB layout and
external noise. The crystal should be placed as close as possible to the XTAL pins on the device. The
traces should be as short as possible and shielded with ground plane from any other traces which could
introduce noise or interference. Crystal loading capacitors should be referenced to AGND.
15.5. External RC Example
If an RC network is used as an external oscillator source for the MCU, the circuit should be configured as
shown in Figure 15.1, Option 2. The capacitor should be no greater than 100 pF; however for very small
capacitors, the total capacitance may be dominated by parasitic capacitance in the PCB layout. To deter-
mine the required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, first
select the RC network value to produce the desired frequency of oscillation. If the frequency desired is
100 kHz, let R = 246 k and C = 50 pF:
f = 1.23( 10
Referring to the table in Figure 15.5, the required XFCN setting is 010.
15.6. External Capacitor Example
If a capacitor is used as an external oscillator for the MCU, the circuit should be configured as shown in
Figure 15.1, Option 3. The capacitor should be no greater than 100 pF; however for very small capacitors,
the total capacitance may be dominated by parasitic capacitance in the PCB layout. To determine the
required External Oscillator Frequency Control value (XFCN) in the OSCXCN Register, select the capaci-
tor to be used and find the frequency of oscillation from the equations below. Assume VDD = 3.0 V and C
= 50 pF:
f = KF / ( C * VDD ) = KF / ( 50 * 3 )
f = KF / 150
If a frequency of roughly 50 kHz is desired, select the K Factor from the table in Figure 15.5 as KF = 7.7:
f = 7.7 / 150 = 0.051 MHz, or 51 kHz
Therefore, the XFCN value to use in this example is 010.
Step 1. Enable the external oscillator.
Step 2. Wait at least1 ms.
Step 3. Poll for XTLVLD => ‘1’.
Step 4. Switch the system clock to the external oscillator.
3
) / RC = 1.23 ( 10
3
) / [ 246 * 50 ] = 0.1 MHz = 100 kHz
Rev. 1.2
C8051F060/1/2/3/4/5/6/7
175

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