参数资料
型号: MT80C31-30R
厂商: ATMEL CORP
元件分类: 微控制器/微处理器
英文描述: 8-BIT, 30 MHz, MICROCONTROLLER, PQFP44
封装: 1 MM HEIGHT, QFP-44
文件页数: 170/170页
文件大小: 4133K
代理商: MT80C31-30R
99
ATtiny4/5/9/10 [DATASHEET]
8127F–AVR–02/2013
The collision detection is enabled in transmit mode, when the output driver has been disabled. The data line should
now be kept high by the internal pull-up and it is monitored to see, if it is driven low by the external programmer. If
the output is read low, a collision has been detected.
There are some potential pit-falls related to the way collision detection is performed. For example, collisions cannot
be detected when the TPI physical layer transmits a bit-stream of successive logical zeros, or bit-stream of alter-
nating logical ones and zeros. This is because the output driver is active all the time, preventing polling of the
TPIDATA line. However, within a single frame the two stop bits should always be transmitted as logical ones,
enabling collision detection at least once per frame (as long as the frame format is not violated regarding the stop
bits).
The TPI physical layer will cease transmission when it detects a collision on the TPIDATA line. The collision is sig-
nalized to the TPI access layer, which immediately changes the physical layer to receive mode and goes to the
error state. The TPI access layer can be recovered from the error state only by sending a BREAK character.
14.3.10
Direction Change
In order to ensure correct timing of the half-duplex operation, a simple guard time mechanism has been added to
the physical layer. When the TPI physical layer changes from receive to transmit mode, a configurable number of
additional IDLE bits are inserted before the start bit is transmitted. The minimum transition time between receive
and transmit mode is two IDLE bits. The total IDLE time is the specified guard time plus two IDLE bits.
The guard time is configured by dedicated bits in the TPIPCR register. The default guard time value after the phys-
ical layer is initialized is 128 bits.
The external programmer looses control of the TPIDATA line when the TPI target changes from receive mode to
transmit. The guard time feature relaxes this critical phase of the communication. When the external programmer
changes from receive mode to transmit, a minimum of one IDLE bit should be inserted before the start bit is
transmitted.
14.4
Access Layer of Tiny Programming Interface
The TPI access layer is responsible for handling the communication with the external programmer. The communi-
cation is based on message format, where each message comprises an instruction followed by one or more byte-
sized operands. The instruction is always sent by the external programmer but operands are sent either by the
external programmer or by the TPI access layer, depending on the type of instruction issued.
The TPI access layer controls the character transfer direction on the TPI physical layer. It also handles the recov-
ery from the error state after exception.
The Control and Status Space (CSS) of the Tiny Programming Interface is allocated for control and status registers
in the TPI access Layer. The CSS consist of registers directly involved in the operation of the TPI itself. These reg-
ister are accessible using the SLDCS and SSTCS instructions.
The access layer can also access the data space, either directly or indirectly using the Pointer Register (PR) as the
address pointer. The data space is accessible using the SLD, SST, SIN and SOUT instructions. The address
pointer can be stored in the Pointer Register using the SLDPR instruction.
14.4.1
Message format
Each message comprises an instruction followed by one or more byte operands. The instruction is always sent by
the external programmer. Depending on the instruction all the following operands are sent either by the external
programmer or by the TPI.
The messages can be categorized in two types based on the instruction, as follows:
Write messages. A write message is a request to write data. The write message is sent entirely by the external
programmer. This message type is used with the SSTCS, SST, STPR, SOUT and SKEY instructions.
相关PDF资料
PDF描述
MV80C31-36D 8-BIT, 36 MHz, MICROCONTROLLER, PQFP44
MS80C51T-30R 8-BIT, MROM, 30 MHz, MICROCONTROLLER, PQCC44
MV80C31-30R 8-BIT, 30 MHz, MICROCONTROLLER, PQFP44
MS80C51C-16R 8-BIT, MROM, 16 MHz, MICROCONTROLLER, PQCC44
MF280C31-30R 8-BIT, 30 MHz, MICROCONTROLLER, PQFP44
相关代理商/技术参数
参数描述
MT80C31BH 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Intel 功能描述:
MT80C51BH 制造商:ROCHESTER 制造商全称:ROCHESTER 功能描述:CMOS SINGLE - CHIP 8-BIT MICROCOMPUTER 64K program Memory Space
MT80C51FB 制造商:Rochester Electronics LLC 功能描述:- Bulk
MT80C51FB/B 制造商:Intel 功能描述:
MT80GB 制造商:Datak Corporation 功能描述: