CN1564001A - Portable signal generating method and system based on USB mobile memory tech - Google Patents

Abstract

The invention belongs to medical electronic equipment. Read/write determination is carried out for main computer by single chip through USB in order to implement USB removal storage device class. External interrupt and counter interrupt are generated through keystroke. Counter interrupt executes operation of forwarding searching file by date, and external interrupt is in reverse. With data files being found, data in file are red out in sequence based on frequency interrupted by timer. After D/A conversion, output of analog signal is formed. Several global variables for reading file data in sequence are defined in time of outputting data. Block diagram is also disclosed in the invention. The system is portable, easy of use and safe.

Description

Portable signal method for generation and system based on USB mobile storage technology

Technical field

Portable signal method for generation and system based on USB mobile storage technology belong to technical field of signal generation, and especially the field takes place the physiological signal in the medical electronics.

Background technology

The research and development of electronic device that are applied to signal Processing at present are more extensive, and in the R﹠D process of signal Processing, often wish by some typical signals equipment to be debugged and detected, and promptly need to use signal generator.With the electrocardio instrument in the medical Instrument field is example, usually needs to use some normal electrocardiosignals in the electrocardio instrument R﹠D process, or reflects the performance that the representative electrocardiosignal of some electrocardio disease comes checkout equipment.And the electrocardiogram (ECG) data type that existing electrocardiosignal generator often can provide is more single, kind is few, data are non-renewable, perhaps the renewal inconvenience of data.The present invention combines USB mobile storage technology on the basis of having adopted FLASH memory technology, singlechip technology and DA output, make the user more simple and efficient to the processing of data, the power transfer module of 3V commentaries on classics 5V makes the present invention to use safety and portable more by No. 5 powered battery of two joints in addition.

The invention brief introduction

The object of the present invention is to provide a kind of practical safety, simple, fast signal generator.

Summarize principle of work of the present invention below: with 51 single-chip microcomputers is core control usb circuit, FLASH memory chip and DA conversion chip, and the power-switching circuit of 3V commentaries on classics 5V provides the power supply of operate as normal for entire equipment.8051 single-chip microcomputers are realized accurate timer cycle with the interruption of timer 0.Single Chip Microcomputer (SCM) program is sought data file from the FAT file system of FLASH storer, the data of sense data file and by DA conversion form output successively in each timer cycle with simulating signal, be equivalent to the data file is once simulated playing process, from the beginning play afterwards at the end that arrives file again.But change the signal magnitude of exporting and be generally the volt level,, by digital regulation resistance the signal that lies prostrate level is carried out dividing potential drop and make it to decay to the millivolt level for the physiological signal such as the electrocardiosignal of simulation reality better through DA.Single-chip microcomputer is with the mode and the communication of USB interface chip of interruption and I in addition, comprised the realization of the USBMass Storage equipment class of USB1.1 standard and Bulk Only mode in the internal processes of single-chip microcomputer, make PC to the data manipulation of equipment just as simple and efficient, as shown in Figure 6 to the operation of a USB mobile disk.

Method of the present invention is characterised in that: deposit in the single-chip microcomputer and realized that USB1.1 standard and USB movable storage device class and FAT file read the firmware program of exporting with DA, it includes following steps successively:

(1). the main end points of configuration USB interface chip is the bulk transfer end points, is respectively Bulk-In and Bulk-Out end points;

(2). main frame at first sends the command block bag by the Bulk-Out end points to the USB interface chip, explains with CBW;

(3). the interrupt register of single-chip microcomputer cycle detection USB interface chip if having, is then carried out following USB transmission process program to have judged whether that USB interrupts producing;

(4). operation USB transmission process program, it includes following steps successively:

(4.1). single-chip microcomputer is read CBW from the Bulk-Out end points of USB interface chip,

(4.2). is judgement that data output is denied? if data output is then from Bulk-Out end points sense data; If the data input, then single-chip microcomputer sends data to the Bulk-In end points;

(4.3). if step (4.2) is finished, then single-chip microcomputer, is represented with CSW to main frame return command state bag from the Bulk-In end points;

(5). in step (3),, then judge to have or not external interrupt or counter to interrupt with the execute file search utility if there is not USB to interrupt; If external interrupt arranged, single-chip microcomputer in the root directory of FAT12 file system according to file date search file backward successively; If there is counter to interrupt, single-chip microcomputer is according to file date search file forward successively;

Interruption is to produce by buttons different in the system to external interrupt with timer;

(6). described file search program contains successively and has the following steps:

(6.1). read the information of the All Files in the root directory of FAT12 file system;

(6.2). interrupt for counter, find out all files more Zao than the current file date;

For external interrupt, find out the file that all upgraded than the current file date;

(6.3). judge whether to have found qualified file.

Interrupt for counter, if no qualified file is then chosen up-to-date file of date in the root directory;

If have, then select up-to-date file of date in the qualified file;

For external interrupt, if no qualified file is then selected date file the earliest in the root directory; If have, then select date file the earliest in the qualified file;

(7). in the timer interrupt handling routine of the timer down trigger by certain frequency, successively the data of selected current data file are read and carry out the DA converted output signal; It comprises following step successively:

(7.1). sense data and carry out DA conversion from the pFlash address, the nCount value that is used for writing down the byte number of reading from current file simultaneously adds one;

(7.2). judge whether the nCount value equates with current file length;

(7.2.1). if equate, then begin reading again from the current file head: the zero clearing of nCount value, give value with the value of the starting cluster of file when prevariety, represent with nCluster;

(7.2.2). if unequal, the value of nCount is 512 multiple simultaneously, then finds next bunch value and gives nCluster by the FAT table;

(7.2.3). if the nCount value promptly is not equal to current file length, multiple that neither 512, then the value of pFlash adds one, withdraws from the timer interrupt handling routine then;

(7.3). in execution of step (7.2.1) and (7.2.3) afterwards, recomputate the pFlash value and withdraw from the timer interrupt handling routine according to the formula pFlash=nCluster * 512+0x4600 in the FAT12 file system;

System of the present invention is characterised in that it contains:

Single-chip microcomputer, it is a chip 89C52;

The USB interface chip, it is a chip PDIUSBD12, it and above-mentioned 89C52 chip interconnect link to each other with PC through usb bus again simultaneously;

The FLASH storer, it is a chips W 29C020C, with above-mentioned 89C52 single-chip microcomputer interconnection;

The DA converter, it is a chip MAX5354, its control end links to each other with the output terminal of above-mentioned 89C52 with input end;

Be output as the voltage source of 2.5V, it is a chip MAX873, and its voltage output end links to each other with the reference voltage input terminal of said chip MAX5354;

Digital regulation resistance, it is a chip DS1689, and its input end links to each other with the signal output part of said chip MAX5354, and making output signal is millivolt level signal by the signal attenuation of volt level;

Electric pressure converter, it is a chip MAX1674, its input termination 3V battery, its 5V voltage output end link to each other with each power input of above-mentioned PDIUSBD12,89C52, W29C020C, MAX5354, DS1689, MAX873 respectively.

Experiment showed, that the present invention has: advantages such as Data Update is convenient, processing is simple and direct, safe in utilization, portable.

Description of drawings

Fig. 1, overall framework figure of the present invention.

Fig. 2, usb interface module circuit diagram.

Fig. 3, single chip machine controlling circuit and FLASH memory circuit figure.

Fig. 4, DA change-over circuit and digital regulation resistance bleeder circuit figure.

Fig. 5, power transfer module circuit diagram.

Fig. 6, equipment insert the synoptic diagram of PC.

Fig. 7, major cycle process flow diagram.

The process flow diagram of Fig. 8, USB transmission process routine.

Fig. 9, file search process flow diagram.

Read file data during Figure 10, timer interrupt and carry out DA transformation flow figure.

Describe a kind of specific embodiment of the present invention in conjunction with the accompanying drawings in detail:

8051 selected compatible single-chip microcomputers of present embodiment are 89C52 of Atmel company, and its inside carries the Flash program storage of 8K and the data-carrier store of 256 bytes, can satisfy the requirement of control program.Selected FLASH storer is the W29C020C chip of Winbond company, and its capacity is 256KB, the I mode.Selected DA chip is MAX5354, and 10 bit serial DA chips provide the DA reference voltage of 2.5V by the MAX873 chip for it in addition.Selected digital regulation resistance is DS1689.Selected power conversion chip is MAX1674.

Fig. 1 is the overall framework figure of present embodiment.System is core devices with 89C52, links to each other with the usb bus of PC by USB interface chip PDIUSBD12.The data transmission of 89C52 control D12 chip, the read-write operation of control FLASH chips W 29C020C and the DA output of MAX5354.The 3V voltage transitions that MAX1674 provides No. 5 batteries of two joints is that 5V uses for other modules of system.The MAX873 chip makes that for the DA of MAX5354 exports the reference voltage that 2.5V is provided the DA output area of MAX5354 is 0-2.5V.The user can select directly to use the volt level signal of MAX5354 output, also can select the signal through the mV level that obtains after the digital regulation resistance DS1689 dividing potential drop.

Fig. 2 is the usb interface module circuit, based on the USB interface chip PDIUSBD12 of Philips company, adds filtering circuit, start-oscillation circuit, USB socket and build-out resistor (R5, R6), and the GoodLink light emitting diode D1 that shows the USB duty.This part circuit is extracted separately as a separate equipment module in the present embodiment, and the mode by socket is connected with Single Chip Microcomputer (SCM) system.J0 in the circuit diagram, J1 are 2 * 10 socket interface.

Fig. 3 is single-chip microcomputer and FLASH memory chip circuit diagram.The 89C52 Single Chip Microcomputer (SCM) system also comprise its peripheral reset circuit (R02, C07) and start-oscillation circuit (X01, C01, C02).The capacity of FLASH memory chip W29C020 is the 256K byte, 8 data lines and 18 address wires are arranged, the normal addressing range of 64K that has exceeded 8051 series monolithics, so 89C52 controls high address A16, the A17 of W29C020C with two IO mouth P10, P11.The 74HC373 chip is used for the address latch of P0 mouth.The P13 mouth of 89C52 connects the Enable Pin (CS0) of USB interface chip D12, and P13 process phase inverter 74HC04 (U04A) connects the Enable Pin (CS1) of FLASH chips W 29C020C, and 89C52 can switch in gating IO control between Flash chip and the USB chip by the control to the P13 mouth like this.Two buttons (S01, S02) connect external interrupt 1 (INT1) sum counter 1 (T1) pin of 89C52 respectively, can produce this two type of interrupt requests by button.89C52 links to each other with the USB modular circuit by two sockets (J01, J02), the D12 chip is carried out data I control and interrupt control, and provide power supply for the USB module.89C52 also controls DA conversion chip MAX5354 by three IO mouths respectively in addition, is respectively P15 (DACS), P16 (DIN) and P34 (DACLK).

Fig. 4 is the DA output circuit, and MAX5354 is one 10 a Serial Control DA conversion chip, and 89C52 is by DACS, and the several pins of DIN and DACLK come the DA conversion of MAX5354 is controlled.The MAX873 chip provides 2.5V reference voltage for the DA conversion of MAX5354.J11 is the mono headset socket, can directly export the signal of the DA conversion of MAX5354.And DS1689 is a digital regulation resistance, and maximum value is 10K, and connecting with 10 Ohmage R11 to get millesimal dividing potential drop, can obtain millivolt level signal.Export by another earphone socket J12.Thereby digital regulation resistance can be regulated the ratio of the resistance control dividing potential drop of digital regulation resistance by two button S11, S12 in addition.

Fig. 5 is the power transfer module circuit diagram.By socket JP the 3V power supply that battery case provides is introduced, the MAX1674 chip is converted to 5V (VCC) output supply total system.RP0 is a magnetic bead in addition, is used for digitally and simulates filtering between the ground, and the output of protection simulating signal is not disturbed by digital signal.

The software section of present embodiment refers to the firmware program (Firmware) that is solidificated in the 89C52 single-chip microcomputer, mainly comprises two aspects, the realization of first USB movable storage device class, and it two is the read operation of FAT file system and DA conversion.And program mainly is divided into two parts from structure: the main circulating program that first single-chip microcomputer constantly circulates and carries out, it two is timer interrupt handling routines.Fig. 7 is the process flow diagram of main circulating program, can see that in main circulating program single-chip microcomputer judges whether that with the interrupt register of cycle detection USB interface chip D12 the communication affairs that main frame arrives USB interface produce with operation USB transmission process routine.Also circulate in the major cycle in addition the external interrupt of button S01 generation, the counter that button S02 produces are interrupted detecting with the execute file search operaqtion.And timer to interrupt mainly being to call over successively and carry out DA conversion output by the data that accurate timing will be stored in the file among the FLASH, Figure 10 is hereinafter to be described specifically the process flow diagram of timer interruption.

Fig. 8 is the main process flow diagram of USB transmission process routine.The single-chip microcomputer firmware program of present embodiment is followed USB1.1 standard (USB1.1 Specifications) and USB mobile storage class bulk transfer protocol (USB Mass Storage Class Bulk OnlyTransport), the a pair of basic end points of USB interface chip D12 (Generic Enpdoint) does not dispose, and main end points (MainEndpoint) is configured to the end points (being respectively Bulk-In and Bulk-Out end points) of a pair of bulk transfer.Can be seen that by Fig. 8 the communication modes of PC main frame and USB mobile storage kind equipment is as follows under the Bulk-Only mode: it is the CBW (Command Block Wrapper, i.e. command block bag) of 31 bytes that main frame at first sends size by the Bulk-Out end points to equipment.Specific label and Host Command have been comprised among the CBW.Equipment comes the order of further processing host according to the specifying information of CBW.And equipment returns the CSW that size is 13 bytes (Command Status Wrapper, i.e. coomand mode bag) by the Bulk-In end points to main frame, with this disposition to main frame report CBW.CSW has comprised and corresponding label of CBW and status information.If the order of Data-Out (data output) type generally is Write order (write order), equipment will and write the proper address of Flash from Bulk-Out end points sense data, return CSW from the Bulk-In end points then; If the order of Data-In (data are read in) type, be generally Read order (read command), equipment will from Flash suitably sense data and send to main frame by the Bulk-In end points, return CSW then; If there is not the order of data transmission, whether to order normally such as testing apparatus, equipment will directly return CSW by the Bulk-In end points to main frame.

USB FLASH dish need format when inserting the Windows system for the first time, according to the big or small Windows of FLASH memory span in the USB mobile disk disc format is turned to FAT12 or FAT16 formatted file system.The difference of FAT12 and FAT16 is that each unit of the FAT table of file system is 12, and FAT16 is 16.The FLASH storer is 256KB in the present embodiment, and Windows is formatted as it FAT12 system automatically.

If the just simple design of considering the USB movable storage device, the processing of the totally unnecessary consideration file system of that deviser.Because after equipment inserts the Windows system for the first time, the formatting command that the user can selective system is formatted into the FAT file system with the USB displacement disc, and comes storing data files according to the form of FAT file system.And for equipment, the concrete structure of FAT file system need not to consider, the Windows system is converted to formatting command Write order automatically, and device just is carried out the order of the Write among the CBW, and the proper address that the data that main frame is sended over are write Flash gets final product.But another major function of the present invention is a signal generator, so equipment need analyze the FAT file system, therefrom finds data file and successively the data in the data file is read according to the frequency of timer and carry out DA conversion output.

Usually can store not only data file inside considering USB FLASH displacement disc, produce the file search function of external interrupt sum counter interruption respectively with starting outfit by button S01, S02.System will select a up-to-date file of date in the root directory to carry out round-robin DA conversion output as current file under the default situations, producing the counter interrupting device by button S02 will be according to file date search file forward successively, makes equipment according to file date search file backward successively and produce external interrupt by button S01.The search of file is to carry out in the FDT of FAT12 file system (root directory table) district, the inside has comprised the information of the All Files under the root directory, comprise filename, file type, file attribute, file date, file size, the starting cluster of file information such as (Starting Cluster).With " forward direction " search is example, and Fig. 9 has described the process flow diagram of search file in FDT, and program at first reads the information of each file among the FDT, therefrom finds out all files more Zao than the current file date.If do not find a qualified file, illustrate that then current file has been a file the earliest, then again current file is made as up-to-date file.And if find qualified file, then therefrom option date a up-to-date file as current file.So just realized that the user whenever presses primary key when having stored a plurality of data file in the USB displacement disc, the function of current file just can be switched by date successively in system.

One bunch (Cluster) in each corresponding data district, unit in the FAT table bunch is the base unit of file storage in the FAT system, and each bunch is 512 bytes.Each bunch in FAT table corresponding unit record be hereof with address when the back to back next one of prevariety bunch.

Present embodiment carries out accurate timing by the timer 0 of 89C52, reads the data in the current file successively and carry out DA conversion output in the timer Interrupt Process.Program has defined the order that several global variables are used for file data and read: nCount is used to write down the byte number of having read from current file, pFlash is a pointer, be used to write down the specific address of the current Flash of reading chip, nCluster is used for the position when prevariety of log file.Figure 10 has described the treatment scheme that timer interrupts.Program is at first at first from pFlash address sense data and carry out DA conversion, simultaneously nCount value oneself add one.Then the nCount value is judged.If nCount value and FileSize (file size) equate, then explanation has arrived last byte of end-of-file, then begin reading again: with the zero clearing of nCount value from the current file head, the nCluster value is changed to StartingCluster, be the starting cluster of file, the formula according to " pFlash=nCluster * 512+0x4600 " in the FAT12 file system recomputates the pFlash address then.The nCount value is 512 multiple if do not run through file as yet, and the data that run through when prevariety are described, then finds the value of next Cluster to give nCluster by the FAT table, and recomputates pFlash.If nCount both had been not equal to the multiple that file size neither 512, then explanation only needs pFlash value is added one certainly when the data of prevariety do not run through as yet in this case, withdraws from Interrupt Process then and gets final product.

Claims (2)

1. based on the portable signal method for generation and the system of USB mobile storage technology, it is characterized in that, deposit in the single-chip microcomputer and realized that USB1.1 standard and USB movable storage device class and FAT file read the firmware program of exporting with DA, it includes following steps successively:

(1). the main end points of configuration USB interface chip is the bulk transfer end points, is respectively Bulk-In and Bulk-Out end points;

(2). main frame at first sends the command block bag by the Bulk-Out end points to the USB interface chip, explains with CBW;

(3). the interrupt register of single-chip microcomputer cycle detection USB interface chip if having, is then carried out following USB transmission process program to have judged whether that USB interrupts producing;

(4). operation USB transmission process program, it includes following steps successively:

(4.1). single-chip microcomputer is read CBW from the Bulk-Out end points of USB interface chip,

(4.2). is judgement that data output is denied? if data output is then from Bulk-Out end points sense data;

If the data input, then single-chip microcomputer sends data to the Bulk-In end points;

(4.3). if step (4.2) is finished, then single-chip microcomputer, is represented with CSW to main frame return command state bag from the Bulk-In end points;

(5). in step (3),, then judge to have or not external interrupt or counter to interrupt with the execute file search utility if there is not USB to interrupt; If external interrupt arranged, single-chip microcomputer in the root directory of FAT12 file system according to file date search file backward successively; If there is counter to interrupt, single-chip microcomputer is according to file date search file forward successively;

Interruption is to produce by buttons different in the system to external interrupt with timer;

(6). described file search program contains successively and has the following steps:

(6.1). read the information of the All Files in the root directory of FAT12 file system;

(6.2). interrupt for counter, find out all files more Zao than the current file date;

For external interrupt, find out the file that all upgraded than the current file date;

(6.3). judge whether to have found qualified file.

Interrupt for counter, if no qualified file is then chosen up-to-date file of date in the root directory;

If have, then select up-to-date file of date in the qualified file;

For external interrupt, if no qualified file is then selected date file the earliest in the root directory; If have, then select date file the earliest in the qualified file;

(7). in the timer interrupt handling routine of the timer down trigger by certain frequency, successively the data of selected current data file are read and carry out the DA converted output signal; It comprises following step successively:

(7.1). sense data and carry out DA conversion from the pFlash address, the nCount value that is used for writing down the byte number of reading from current file simultaneously adds one;

(7.2). judge whether the nCount value equates with current file length;

(7.2.1). if equate, then begin reading again from the current file head: the zero clearing of nCount value, give value with the value of the starting cluster of file when prevariety, represent with nCluster;

(7.2.2). if unequal, the value of nCount is 512 multiple simultaneously, then finds next bunch value and gives nCluster by the FAT table;

(7.2.3). if the nCount value promptly is not equal to current file length, multiple that neither 512, then the value of pFlash adds one, withdraws from the timer interrupt handling routine then;

(7.3). in execution of step (7.2.1) and (7.2.3) afterwards, according to the formula pFlash=in the FAT12 file system

NCluster * 512+0x4600 recomputates the pFlash value and withdraws from the timer interrupt handling routine;

2. based on the portable signal method for generation and the system of USB mobile storage technology, it is characterized in that it contains: single-chip microcomputer, it is a chip 89C52;

The USB interface chip, it is a chip PDIUSBD12, it and above-mentioned 89C52 chip interconnect link to each other with PC through usb bus again simultaneously;

The FLASH storer, it is a chips W 29C020C, with above-mentioned 89C52 single-chip microcomputer interconnection;

The DA converter, it is a chip MAX5354, its control end links to each other with the output terminal of above-mentioned 89C52 with input end;

Be output as the voltage source of 2.5V, it is a chip MAX873, and its voltage output end links to each other with the reference voltage input terminal of said chip MAX5354;

Digital regulation resistance, it is a chip DS1689, and its input end links to each other with the signal output part of said chip MAX5354, and making output signal is millivolt level signal by the signal attenuation of volt level;

Electric pressure converter, it is a chip MAX1674, its input termination 3V battery, its 5V voltage output end link to each other with each power input of above-mentioned PDIUSBD12,89C52, W29C020C, MAX5354, DS1689, MAX873 respectively.

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