参数资料
型号: AT80C51RB2-RLTIM
厂商: Atmel Corp.
英文描述: 80C51 High Performance ROM 8-bit Microcontroller
中文描述: 80C51的高性能ROM的8位微控制器
文件页数: 35/83页
文件大小: 672K
代理商: AT80C51RB2-RLTIM
36
AT80C51RD2/AT83C51Rx2
4113B–8051–03/05
Figure 16.
UART Timings in Modes 2 and 3
Automatic Address
Recognition
The automatic address recognition feature is enabled when the multiprocessor commu-
nication feature is enabled (SM2 bit in SCON register is set).
Implemented in hardware, automatic address recognition enhances the multiprocessor
communication feature by allowing the serial port to examine the address of each
incoming command frame. Only when the serial port recognizes its own address, the
receiver sets RI bit in SCON register to generate an interrupt. This ensures that the CPU
is not interrupted by command frames addressed to other devices.
If desired, you may enable the automatic address recognition feature in mode 1. In this
configuration, the stop bit takes the place of the ninth data bit. Bit RI is set only when the
received command frame address matches the device’s address and is terminated by a
valid stop bit.
To support automatic address recognition, a device is identified by a given address and
a broadcast address.
Note:
The multiprocessor communication and automatic address recognition features cannot
be enabled in mode 0 (i.e. setting SM2 bit in SCON register in mode 0 has no effect).
Given Address
Each device has an individual address that is specified in SADDR register; the SADEN
register is a mask byte that contains don’t care bits (defined by zeros) to form the
device’s given address. The don’t care bits provide the flexibility to address one or more
slaves at a time. The following example illustrates how a given address is formed.
To address a device by its individual address, the SADEN mask byte must be
1111
1111b
.
For example:
SADDR0101 0110b
SADEN1111 1100b
Given0101 01XXb
The following is an example of how to use given addresses to address different slaves:
Slave A:SADDR1111 0001b
SADEN1111 1010b
Given1111 0X0Xb
Slave B:SADDR1111 0011b
SADEN1111 1001b
Given1111 0XX1b
Slave C:SADDR1111 0010b
SADEN1111 1101b
Given1111 00X1b
RI
SMOD0 = 0
Data Byte
Ninth
Bit
Stop
Bit
.Start
Bit
RXD
D8
D7
D6
D5
D4
D3
D2
D1
D0
RI
SMOD0 = 1
FE
SMOD0 = 1
相关PDF资料
PDF描述
AT80C51RB2-RLTUL 80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-RLTUM 80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-SLSCM 80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-SLSIL 80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-SLSIM 80C51 High Performance ROM 8-bit Microcontroller
相关代理商/技术参数
参数描述
AT80C51RB2-RLTUL 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-RLTUM 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-SLSCM 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-SLSIL 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:80C51 High Performance ROM 8-bit Microcontroller
AT80C51RB2-SLSIM 制造商:ATMEL 制造商全称:ATMEL Corporation 功能描述:80C51 High Performance ROM 8-bit Microcontroller