C8051F413-GM Silicon Laboratories Inc, C8051F413-GM Datasheet - Page 169

• Manufacturer Part Number: C8051F413-GM
• Description: IC 8051 MCU 16K FLASH 28QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F41xr

Specifications of C8051F413-GM

• Program Memory Type: FLASH
• Program Memory Size: 16KB (16K x 8)
• Package / Case: 28-QFN
• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 50MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 20
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.25 V
• Data Converters: A/D 20x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: C8051F4x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 2.25 KB
• Interface Type: I2C/SMBus/SPI/UART
• Maximum Clock Frequency: 50 MHz
• Number Of Programmable I/os: 20
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F410DK
• Minimum Operating Temperature: - 40 C
• On-chip Dac: 2-ch x 12-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 770-1006 - ISP 4PORT FOR SILABS C8051F MCU336-1454 - ADAPTER PROGRAM TOOLSTICK F411336-1317 - KIT EVAL FOR C8051F411336-1314 - KIT DEV FOR C8051F41X
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1311

When the crystal oscillator is first enabled, the oscillator amplitude detection circuit requires a settling time
to achieve proper bias. Introducing a delay of 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 rec-
ommended procedure is:
Note: Tuning-fork crystals may require additional settling time before XTLVLD returns a valid result.
The capacitors shown in the external crystal configuration provide the load capacitance required by the
crystal for correct oscillation. These capacitors are "in series" as seen by the crystal and "in parallel" with
the stray capacitance of the XTAL1 and XTAL2 pins.
Note: The load capacitance depends upon the crystal and the manufacturer. Please refer to the crystal
data sheet when completing these calculations.
For example, a tuning-fork crystal of 32.768 kHz with a recommended load capacitance of 12.5 pF should
use the configuration shown in Figure 19.1, Option 1. The total value of the capacitors and the stray capac-
itance of the XTAL pins should equal 25 pF. With a stray capacitance of 3 pF per pin, the 22 pF capacitors
yield an equivalent capacitance of 12.5 pF across the crystal, as shown in Figure 19.2.
Important Note on External Crystals: Crystal oscillator circuits are quite sensitive to PCB layout. 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.
Step 1. Force the XTAL1 and XTAL2 pins low by writing 0's to the port latch.
Step 2. Configure XTAL1 and XTAL2 as analog inputs.
Step 3. Release the crystal pins by writing ‘1's to the port latch.
Step 4. Enable the external oscillator.
Step 5. Wait at least 1 ms.
Step 6. Poll for XTLVLD => '1'.
Step 7. Switch the system clock to the external oscillator.
Figure 19.2. 32.768 kHz External Crystal Example
32.768 kHz
22 pF
22 pF
Rev. 1.1
10 M

C8051F410/1/2/3
XTAL1
XTAL2
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