C8051F337-GM Silicon Laboratories Inc, C8051F337-GM Datasheet - Page 117

• Manufacturer Part Number: C8051F337-GM
• Description: IC MCU 16K FLASH 20QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F33xr

Specifications of C8051F337-GM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 17
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QFN
• Processor Series: C8051F3x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: I2C, SPI, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 4
• Operating Supply Voltage: 2.7 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: KSK-SL-TOOLSTICK, PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F336DK
• Minimum Operating Temperature: - 40 C
• For Use With: 336-1451 - ADAPTER PROGRAM TOOLSTICK F330
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details
• Other names: 336-1428-5

where f = the frequency of oscillation in MHz, C = the capacitor value in pF, and R = the pull-up resistor
value in kΩ.
19.4.2. 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 19.1, 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, according to Equation 19.1,
For example: If the frequency desired is 100 kHz, let R = 246 kΩ and C = 50 pF:
f = 1.23( 10
Referring to the table in SFR Definition 19.5, the required XFCN setting is 010b.
Figure 19.2. External 32.768 kHz Quartz Crystal Oscillator Connection Diagram
3
) / RC = 1.23 ( 10
Equation 19.1. RC Mode Oscillator Frequency
22pF*
* Capacitor values depend on
3
crystal specifications
) / [ 246 x 50 ] = 0.1 MHz = 100 kHz
32.768 kHz
10MΩ
f
=
1.23 10
Rev.1.0
×
22pF*
3
⁄
(
R C
×
)
XTAL1
XTAL2
C8051F336/7/8/9
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