Datasheet 搜索 > 微控制器 > Microchip（微芯） > PIC16LF876A-I/ML 数据手册 > PIC16LF876A-I/ML 用户编程技术手册 1/8 页
器件3D模型￥ 53.833
PIC16LF876A-I/ML 用户编程技术手册 - Microchip（微芯）
制造商:
Microchip（微芯）
分类:
微控制器
封装:
QFN-28
描述:
PIC16F873A/874A/876A/877A 8 位闪存微控制器### PIC16 微控制器
Pictures:
3D模型
符号图
焊盘图
引脚图
产品图
页面导航:
技术参数、封装参数在P2P3
电气规格在P3
导航目录
PIC16LF876A-I/ML数据手册
Page:
of 8 Go
若手册格式错乱，请下载阅览PDF原文件
© 2005 Microchip Technology Inc. DS91087A-page 1
TB087
INTRODUCTION
Even though many microcontrollers offer an on-chip
brown-out function, it may be desirable to use an
external voltage supervisor. This may be due to the
microcontroller’s limited trip point selections or the
additional current requirement for enabling the brown-
out function. In these cases, an external voltage
supervisor device may be preferable.
Many standard microcontrollers are Flash memory
devices. This means that the device can be
programmed in-circuit. Typically, to enter the in-circuit
programming mode, some non-typical state needs to
be forced. For PICmicro
®
microcontrollers, the mode is
called In-Circuit Serial Programming™ (ICSP™). A
typical microcontroller – ICSP system is shown in
Figure 1.
ICSP can be used to program the device after
assembly as well as for firmware updates in the field.
In most cases, entering the ICSP mode requires that
the MCLR
pin go from a low voltage (V
IL
) to the
programming high voltage (V
IHH
). The V
IHH
is
dependent on the PICmicro microcontroller and
typically ranges from a minimum of the PICmicro
microcontroller’s V
DD
+ 3.5V to a maximum of 14V.
As can be expected, these voltages are beyond the
maximum voltage specification of the voltage
supervisor output pin.
This technical brief will show how the MCP111 and
MCP121 may be used in PICmicro microcontroller
systems where ICSP is required.
Reset Characteristics
The two main reasons to consider an external voltage
supervisor device are:
1. Voltage trip point
2. Operating current
Table 1 shows a voltage trip point and operational
current comparison between a couple of PICmicro
microcontrollers and either the MCP111 or MCP121.
The MCP1X1 offers more voltage trip points and a
significantly lower operating current.
TABLE 1: RESET CHARACTERISTICS
FIGURE 1: A TYPICAL PICmicro
®
MICROCONTROLLER SYSTEM WITH ICSP™
Note: Refer to the specific programming
specification for the desired PICmicro
microcontroller.
Author: Mark Palmer
Microchip Technology Inc.
Device
Trip Point
Voltages (V)
(Typ.)
Operating
Current (µA)
(min./max.)
PIC16F87XA 4.00 —/200
(1)
PIC18F1320 2.72, 4.22, 4.54 19/45
(1)
MCP121 1.90, 2.32, 2.63, 2.93,
3.08, 4.38, 4.63
—/1.75
MCP111 1.90, 2.32, 2.63, 2.90,
2.93, 3.08, 4.38, 4.63
—/1.75
(2)
Note 1: This current added to either device I
DD or
I
PD
current.
2: Power-up Timer Active current is 20 µA.
This is NOT the typical state.
PICmicro
®
MCU
MCLR/V
PP
R
PU
V
DD
V
DD
V
PP
ICSP™
Connector
Other
Circuitry
Other
Circuitry
Using Voltage Supervisors with PICmicro
®
Microcontroller
Systems which Implement In-Circuit Serial Programming™
器件 Datasheet 文档搜索
AiEMA 数据库涵盖高达 72,405,303 个元件的数据手册，每天更新 5,000 多个 PDF 文件
