参数资料
型号: C8051F018
厂商: Silicon Laboratories Inc
文件页数: 138/154页
文件大小: 0K
描述: IC 8051 MCU 16K FLASH 64TQFP
标准包装: 160
系列: C8051F018
核心处理器: 8051
芯体尺寸: 8-位
速度: 25MHz
连通性: SMBus(2 线/I²C),SPI,UART/USART
外围设备: 欠压检测/复位,POR,PWM,温度传感器,WDT
输入/输出数: 32
程序存储器容量: 16KB(16K x 8)
程序存储器类型: 闪存
RAM 容量: 1.25K x 8
电压 - 电源 (Vcc/Vdd): 2.8 V ~ 3.6 V
数据转换器: A/D 8x10b
振荡器型: 内部
工作温度: -40°C ~ 85°C
封装/外壳: 64-TQFP
包装: 托盘
C8051F018
C8051F019
12.1.
External Crystal Example
If a crystal or ceramic resonator were used to generate the system clock for the MCU, the circuit would be as shown
in Figure 12.1, Option 1. For an ECS-110.5-20-4 crystal, the resonate frequency is 11.0592MHz, the intrinsic
capacitance is 7pF, and the ESR is 60
. The compensation capacitors should be 33pF each, and the PWB parasitic
capacitance is estimated to be 2pF. The appropriate External Oscillator Frequency Control value (XFCN) from the
Crystal column in the table in Figure 12.3 (OSCXCN Register) should be 111b.
Because the oscillator detect circuitry needs time to settle after the crystal oscillator is enabled, software should wait
at least 1ms between enabling the crystal oscillator and polling the XTLVLD bit. The recommend procedure is:
1. Enable the external oscillator
2. Wait at least 1 ms
3. Poll for XTLVLD '0' ==> '1'
4. Switch to the external oscillator
Switching to the external oscillator before the crystal oscillator has stabilized could result in unpredictable behavior.
NOTE: 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, keeping the traces as short as possible and shielded with ground plane from any
other traces which could introduce noise or interference.
12.2.
External RC Example
If an external RC network were used to generate the system clock for the MCU, the circuit would be as shown in
Figure 12.1, Option 2. The capacitor must be no greater than 100pF, but using a very small capacitor will increase
the frequency drift due to the PWB parasitic capacitance. To determine 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 100kHz, let R = 246k
and C = 50pF:
f = 1.23(10
3)/RC = 1.23(103) / [246 * 50] = 0.1MHz = 100kHz
XFCN
log
2 (f/25kHz)
XFCN
log
2 (100kHz/25kHz) = log 2 (4)
XFCN
2, or code 010
12.3.
External Capacitor Example
If an external capacitor were used to generate the system clock for the MCU, the circuit would be as shown in
Figure 12.1, Option 3. The capacitor must be no greater than 100pF, but using a very small capacitor will increase
the frequency inaccuracy due to the PWB parasitic capacitance. To determine the required External Oscillator
Frequency Control value (XFCN) in the OSCXCN Register, select the capacitor to be used and find the frequency
of oscillation from the equations below. Assume AV+ = 3.0V and C = 50pF:
f = KF / (C * VDD) = KF / (50 * 3)
f = KF / 150
If a frequency of roughly 90kHz is desired, select the K Factor from the table in Figure 12.3 as KF = 13:
f = 13 /150 = 0.087MHz, or 87kHz
Therefore, the XFCN value to use in this example is 011.
Rev. 1.2
84
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C8051F019-GQ 功能描述:8位微控制器 -MCU 16KB 10ADC 48P MCU RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT