The summary is odd much chance communication uses a machine commonly means of serial bus line, but be apart from in communication short, communication data bulk is great, the circumstance with communication high rate also can use much machine collateral communication. Article introduction uses simple and logistic circuit one kind to realize sheet piece aircraft much engine is collateral the method of communication. The keyword is collateral communication, register of 3 condition amortize, double port memory, bus line keeps apart 1 brief introduction what the article introduces is odd an aircraft much engine is collateral communication system, use 89C51 serves as lead plane, multichip 89C2051 serves as from machine. (89C2051 is enclosed for 20 feet 300MIL, those who contain 2K FLASH E2PROM is odd a machine, besides little two and outside the mouth, have MCS-51 series sheet piece machine is all function. Because its volume is minor, the function is strong, be sure to be in odd a machine application domain inside use extensively) . Method of this kind of collateral communication is applied to in much site, detect mutiple levelly and the part of communication controller acts as in control system; Also agree with use as odd a machine is serial buccal augment circuit. Graph the logistic graph of 1 chip and state diagram of 4 kinds of jobs 2 sheet piece machine is collateral of 74HC646 of register of amortize of bus line of 2 3 state is in communication principle block diagram odd a much chance that the orgnaization becomes is collateral in communication system, exchange of total on-line information uses PIO commonly (collateral interface) the method such as register of He Shuangduan mouth, auxiliary arbitrate with bus line circuit. The collateral interface chip that uses normally has 8155, 8255 wait. The article introduces a kind of simple collateral interface circuit, it can be replaced already 8255 wait for chip, still can make circuit structure is mixed more simply compact. This circuit is mixed by a 74HC74 a 74HC646 (300MIL is narrow enclose) form. 74HC646 is register of amortize of 3 state bus line, also be a double port shares memory actually, just share memery block very small, only register of input of a data and register of output of a data, regard monomial section as communication data with it temporarily terminal, every are deferent a byte, the handclasp between machine of principal and subordinate, after taking away data, continue again the communication of below one byte. 74HC646 can lock up the data of two bus line respectively put, undertake by chip interior bus line data is exchanged again. 74HC646 has state of 4 kinds of jobs, use the control of status of pair of these 4 kinds of jobs, can realize many sheet piece machine use data mouth to undertake data is exchanged, line of opening of the others below the province does other works, be like drive LED, control switch. The logistic graph of 74HC646 chip and status of 4 kinds of jobs are shown 1 times like the graph. 3 sheet piece machine is collateral logarithm of 74HC646 of communication principle is put according to the lock that have made information intend the work to finish data to exchange only, odd the implementation of communication still must have an opportunity between much chance communication contact method, in order to make odd a working status on machine understanding bus line, avoid to produce bus line conflict. Here uses contact of 4 lines handclasp: Two by send just send receive debit, the announcement receives square data to had gotten ready (if pursue 2 medium TFNE* , RFNE* ) ; Two by receive debit to send send square, the announcement sends square data to had been received (if pursue 2 medium TFNF* , RFNF* ) communication contact signal is by 74HC74 circuit arises. Odd block diagram of collateral communication principle is like a machine the graph is shown 2 times. 4 much chance are collateral the sheet of the collateral communication above communication agreement piece machine keep number in order to prevent engine of principal and subordinate at the same time to 74HC646 without block circuit or at the same time reading, accordingly each stand-alone is in two-way when transmitting, need fibrous root controls next his operations according to state information, have contact namely, cooperate ability to avoid to cause an error through agreement of communication of software, hardware, assure to won't create competitive conflict to 74HC646. Accordingly, besides above besides the contact circuit that tells, when work out software, still must comply with is the following agreement: . When lead plane transmits data to 74HC646, must make sure 74HC646 receives register to be empty. .
Lead plane and should pass 74HC646 according to transmitting from the number between machine, the agreement does not allow both sides to undertake operating to 74HC646 at the same time, need fibrous root controls his operation according to state information. The format of 5 communication agreement and executive process 5.
When the asynchronous communication of 1 news format in collateral communication is transmitted, put in the type of frame and format problem as much, can use the frame pattern with serial similar communication: Diagnostic word long degree occupies 1 data 2 .
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Desired result is piled up 5.
With detecting means is the executive process of a demonstrative communication agreement below the executive process of 2 communication agreement. 5.
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1 lead plane to from machine the process that keep number: (Lead plane is written, from machine read) lead plane keeps data to 74HC646, inform next occupy from machine know exactly about sth come, from machine read access to occupy from inside 74HC646. ① lead plane is read take position, detect TFNF* whether be 0. ② is like TFNF* ＝ 1, lead plane awaits temporarily; Be like TFNF* ＝ 0, lead plane keeps data to 74HC646, make TFNF* ＝ 1, make at the same time TFNE* ＝ 0. ③ from machine read take position, detect TFNE* whether be 0. Be like TFNE* ＝ 1, from machine is temporary await; Be like TFNE* ＝ 0, from machine read data from 74HC646, make TFNE* ＝ 1, make at the same time TFNF* ＝ 0. ④ lead plane detects again condition whether TFNF* is 0, if be " 0 " , specification from machine already took away data from inside 74HC646, lead plane can be sent fall to be occupied. 5.
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2 lead plane read from machine process: (From machine write, lead plane is read) from machine keep data to 74HC646, inform lead plane has data to come next, after lead plane gets signal, take away data from inside 74HC646. ① from machine read take position, detect RFNF* whether be 0. ② is like RFNF*=1, from machine is temporary await; Be like RFNF*=0, from machine keep data to 74HC646, make RFNF*=1, make at the same time RFNE*=0. ③ lead plane is read take position, detect RFNE* whether be 0. Be like RFNE* ＝ 1, lead plane awaits temporarily; Be like RFNE*=0, lead plane reads data from 74HC646, make RFNE* ＝ 1, make at the same time RFNF* ＝ 0. ④ from machine detect again condition whether RFNF* is 0, if be " 0 " , specification from machine already took away data from inside 74HC646, lead plane can be sent fall to be occupied. 6 flow chart (detect means) is used detect the order flow of means is shown 3 times like the graph. Graph 3 use detect if the program flow chart of means is used break pattern, need to be revised slightly to carrying out process and flow chart only can. CNC Milling
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