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PIC18F8620-I/PT 参数 Datasheet PDF下载

PIC18F8620-I/PT图片预览
型号: PIC18F8620-I/PT
PDF下载: 下载PDF文件 查看货源
内容描述: 八十〇分之六十四引脚高性能1 Mbit的增强型闪存微控制器与A / D [64/80-Pin High Performance 1 Mbit Enhanced FLASH Microcontrollers with A/D]
分类和应用: 闪存微控制器和处理器外围集成电路PC时钟
文件页数/大小: 366 页 / 6797 K
品牌: MICROCHIP [ MICROCHIP ]
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PIC18FXX20  
23.4.2  
DATA EEPROM  
TABLE 23-4: DEBUGGER RESOURCES  
CODE PROTECTION  
I/O pins  
Stack  
RB6, RB7  
2 levels  
The entire Data EEPROM is protected from external  
reads and writes by two bits: CPD and WRTD. CPD  
inhibits external reads and writes of Data EEPROM.  
WRTD inhibits external writes to Data EEPROM. The  
CPU can continue to read and write Data EEPROM,  
regardless of the protection bit settings.  
Program Memory  
Data Memory  
Last 576 bytes  
Last 10 bytes  
To use the In-Circuit Debugger function of the micro-  
controller, the design must implement In-Circuit Serial  
Programming connections to MCLR/VPP, VDD, GND,  
RB7 and RB6. This will interface to the In-Circuit  
Debugger module available from Microchip, or one of  
the third party development tool companies.  
23.4.3  
CONFIGURATION REGISTER  
PROTECTION  
The configuration registers can be write protected. The  
WRTC bit controls protection of the Configuration reg-  
isters. In User mode, the WRTC bit is readable only.  
WRTC can only be written via ICSP or an external  
programmer.  
23.8 Low Voltage ICSP Programming  
The LVP bit Configuration register, CONFIG4L,  
enables low voltage ICSP programming. This mode  
allows the microcontroller to be programmed via ICSP  
using a VDD source in the operating voltage range. This  
only means that VPP does not have to be brought to  
VIHH, but can instead be left at the normal operating  
voltage. In this mode, the RB5/PGM pin is dedicated to  
the programming function and ceases to be a general  
purpose I/O pin. During programming, VDD is applied to  
the MCLR/VPP pin. To enter Programming mode, VDD  
must be applied to the RB5/PGM, provided the LVP bit  
is set. The LVP bit defaults to a (‘1’) from the factory.  
23.5 ID Locations  
Eight memory locations (200000h - 200007h) are des-  
ignated as ID locations, where the user can store  
checksum or other code identification numbers. These  
locations are accessible during normal execution  
through the TBLRD and TBLWT instructions, or during  
program/verify. The ID locations can be read when the  
device is code protected.  
23.6  
In-Circuit Serial Programming  
Note 1: The High Voltage Programming mode is  
always available, regardless of the state  
of the LVP bit, by applying VIHH to the  
MCLR pin.  
PIC18FXX20 microcontrollers can be serially pro-  
grammed while in the end application circuit. This is  
simply done with two lines for clock and data, and three  
other lines for power, ground and the programming  
voltage. This allows customers to manufacture boards  
with unprogrammed devices, and then program the  
microcontroller just before shipping the product. This  
also allows the most recent firmware, or a custom  
firmware to be programmed.  
2: While in Low Voltage ICSP mode, the  
RB5 pin can no longer be used as a gen-  
eral purpose I/O pin, and should be held  
low during normal operation.  
3: When using low voltage ICSP program-  
ming (LVP) and the pull-ups on PORTB  
are enabled, bit 5 in the TRISB register  
must be cleared to disable the pull-up on  
RB5 and ensure the proper operation of  
the device.  
Note: When performing in-circuit serial program-  
ming, verify that power is connected to all  
VDD and AVDD pins of the microcontroller,  
and that all VSS and AVSS pins are  
grounded.  
If Low Voltage Programming mode is not used, the LVP  
bit can be programmed to a '0' and RB5/PGM becomes  
a digital I/O pin. However, the LVP bit may only be pro-  
grammed when programming is entered with VIHH on  
MCLR/VPP.  
It should be noted that once the LVP bit is programmed  
to ‘0’, only the High Voltage Programming mode is  
available and only High Voltage Programming mode  
can be used to program the device.  
When using low voltage ICSP, the part must be sup-  
plied 4.5V to 5.5V, if a bulk erase will be executed. This  
includes reprogramming of the code protect bits from  
an on state to an off state. For all other cases of low  
voltage ICSP, the part may be programmed at the nor-  
mal operating voltage. This means unique user IDs, or  
user code can be reprogrammed or added.  
23.7 In-Circuit Debugger  
When the DEBUG bit in Configuration register  
CONFIG4L is programmed to a '0', the In-Circuit  
Debugger functionality is enabled. This function allows  
simple debugging functions when used with MPLAB®  
IDE. When the microcontroller has this feature  
enabled, some of the resources are not available for  
general use. Table 23-4 shows which features are  
consumed by the background debugger.  
2003 Microchip Technology Inc.  
Advance Information  
DS39609A-page 257  
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