Datasheet 搜索 > 微控制器 > Microchip（微芯） > PIC18F97J94-I/PT 数据手册 > PIC18F97J94-I/PT 数据手册 521/696 页
器件3D模型￥ 41.077
PIC18F97J94-I/PT 数据手册 - Microchip（微芯）
制造商:
Microchip（微芯）
分类:
微控制器
封装:
TQFP-100
描述:
MICROCHIP PIC18F97J94-I/PT 微控制器, 8位, 闪存, PIC18FxxJxx, 64 MHz, 128 KB, 3.7714 KB, 100 引脚, TQFP
Pictures:
3D模型
符号图
焊盘图
引脚图
产品图
页面导航:
引脚图在P3P4P5P32P40P264P321P322P324P344P346Hot
典型应用电路图在P357P521
原理图在P11P14P15P16P53P60P85P221P236P245P255P282
封装尺寸在P665
标记信息在P663
封装信息在P663P665P666P667P669P671P673P675
功能描述在P489
技术参数、封装参数在P76P488P551P636P637P638P639P641P642P643
应用领域在P62P72P76P326P333P505
电气规格在P11P33P49P76P90P92P461P485P488P492P497P499
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PIC18F97J94-I/PT数据手册
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2012 Microchip Technology Inc. DS30575A-page 521
PIC18F97J94 FAMILY
26.6 Measuring Time with the CTMU
Module
Time can be precisely measured after the ratio (C/I) is
measured from the current and capacitance calibration
step. To do that:
1. Initialize the A/D Converter and the CTMU.
2. Set EDG1STAT.
3. Set EDG2STAT.
4. Perform an A/D conversion.
5. Calculate the time between edges as T = (C/I) * V,
where:
• I is calculated in the current calibration
step (Section 26.4.1 “Current Source
Calibration”)
• C is calculated in the capacitance calibra-
tion step (Section 26.4.2 “Capacitance
Calibration”)
• V is measured by performing the A/D conversion
It is assumed that the time measured is small enough
that the capacitance, C
AD + CEXT, provides a valid
voltage to the A/D Converter. For the smallest time
measurement, always set the A/D Channel Select bits
via ADCON1L/H to an unused A/D channel; the corre-
sponding pin for which is not connected to any circuit
board trace. This minimizes added stray capacitance,
keeping the total circuit capacitance close to that of the
A/D Converter itself (25 pF).
To measure longer time intervals, an external capacitor
may be connected to an A/D channel and that channel
selected whenever making a time measurement.
FIGURE 26-3: CTMU TYPICAL CONNECTIONS AND INTERNAL CONFIGURATION FOR TIME
MEASUREMENT
PIC18F97J94
A/D Converter
CTMU
CTED1
CTED2
AN
X
A/D Voltage
EDG1
EDG2
CAD
CEXT
Current Source
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