GPIB chip TNT4882 in multi-channel program control power source’s application
August 8, 2008 – 1:47 pmAbstract: Introduces one kind of GPIB bus interface chip TNT4882 and in the multi-channel program control power source’s application, including TNT4882 pin arrangement, internal structure, function and mailing address, and microprocessor’s connection and with superior machine correspondence; Simultaneously gives in the practical application the overall diagram and each major function module software flow and the program control power source and the superior machine signal procedure.
Key word: GPIB main line TNT4882 microprocessor program control power source
GPIB (General Purpose Interface Bus) the interface bus initiates by American HP Corporation to implement most early, the naming is HPIB. As a result of its good connection characteristic, obtains the widespread application very quickly in the international scope, and by the American electricity and the electronic engineering academic society naming is IEEE488, in countries and so on Britain and Japan is called GPIB. Although has many kinds of calls the law, but in fact differs from besides the mechanical standard, its essence is completely same. It just likes a bridge, will dispose the GPIB bus interface the instrument and the computer unifies closely. The system which composes with it convenient, nimble, the function is strong and the compatibility is good, but applies domains conveniently and so on scientific research, project, medicine project, medicine and test.
American NI Corporation produces GPIB special-purpose chip TNT4882 has the function to be strong, the volume is small, transmission speed quick and easily with characteristics and so on microprocessor connection, is subject to the user the favor. The author developed successfully using TNT4882 has had the GPIB bus interface multi-channel program control power source.
Figure 1 TNT4882 pin chart
1 TNT4882 chip synopsis
1.1 TNT4882 pin explanation
TNT4882 is 100 foot PQFQ which NT Corporation develops the seal GPIB special-purpose integration chip, is the IEEE488.2 standard and the GPIB receiving and dispatching function integration, and has the HS488 enhancement function. Its pin as shown in Figure 1.
VDD: The power source, meets 5V;
GND: Power source place;
XTAL0, XTAL1: External connection clock oscillator pin;
DATA15~DATA8 (ABUS), DATA7~DATA0 (BBUS): The data line, is TNT4882 carries on the data feeds/output with exterior CPU the bidirectional bus, divides into ABUS and BBUS, is advantageous carries on 8 or 16 bit data operations;
ABUSN:ABUS enables;
BBUSN:BBUS enables;
ABUS_OEN: Presently is reading the data through ABUS;
BBUS_OEN: Presently is reading the data through BBUS;
CSN: Selecting patches or strips of land as worth saving for seed;
ADDR4~0: Internal register address wire;
RDN: Reads the signal;
WRN: Writes a letter the number;
CPUACC: Instructed that TNT4882 may carry on the main line operation time delay;
RDY1: Instructed that TNT4882 completes the current main line operation;
DRQ:DMA application signal;
DACKN:DMA application answering signal;
BURST_RDN: Reads the signal continuously;
FIFO_RDY: Current TNT4882 internal FIFO had 8 valid data at least;
INTR: Interrupt request signal;
RAGED: Address mapping choice, effective, then maps the internal register to the different address;
MODE:TNT4882 working pattern choice;
SWAPN: Pattern cut;
RESETN: Replacement;
TADCS: Instruction current TNT4882 selects for speaking;
LADCS: Instruction current TNT4882 selects for the listener;
TRIG: Instruction current TNT4882 receives the exterior trigger pip;
DCAS: Instruction current TNT4882 receives the equipment reset signal;
REM: Instruction current TNT4882 enters the remote control condition;
GPIB data line 8: DIO8N~DIO1N, uses in the GPIB issue address and the order, transmits the data;
GPIB management main line 5: ATNN (ATTENTION, attention) the line, IFCN (INTERFACE-CLEAR, interface clear) the line, RENN (REMOTE ENABLE, program control enables) the line, SRQN (SERVICE REQUEST, service request) the line, NDACN (NOT DATA ACCEPTED, has not received data) the line;
GPIB suspension hook main line 3: DAVN (DATA VALID, data effective) line, NRFDN (NOT READY FOR DATA, has not prepared receive) the line, NDACN (NOT DATA ACCEPTED, has not received data) the line. TNT4882 uses the above 3 main lines to carry on the handshake information and the data transfer, guaranteed that the information and the data issue and transmits accurate.
1.2 TNT4882 internal structure
TNT4882 has three kind of patterns: Monolithic pattern, Turbo 7210 pattern and Turbo 9914 pattern, moreover the Turbo 7210 pattern and the Turbo 9914 pattern may transform to the monolithic pattern. The monolithic pattern is the simple, the fastest structure. In the design, selects the monolithic pattern. Monolithic pattern interior composition module as shown in Figure 2.
The monolithic pattern internal structure by 1 internal ISA logical interface, 1 internal reads/writes the controller, 1 internal advanced leaves the first buffer, 1 fixed time/counter, 1 internal interrupt controller, 1 may the configuration state register, 1 IEEE488 main line monitoring device, 1 IEEE488 main line function connection, 1 HS488 electric circuit function connection, 1 IEEE488 transceiver and 1 IEEE488 main line composes.
2 TNT4882 functional control and data transfer/receive way
2.1 TNT4882 functional control
The TNT4882 functional control is through writes the order character the way to realize. These order character including the TNT4882 replacement, the initialization, the register reads/writes and orders and so on interrupt request. The TNT4882 interior has 8 registers which more than 40 users may visit. Is through fills in visit to these register’s reads in the register/writes the order the address to carry on. These registers including basic disposition, FIFO, interrupt control, fixed time/counter, condition register, suspension hook with management register and so on.
2.2 TNT4882 data transfer/receive way
When the transmission data starts, TNT4882 completes the initialization. After the TNT4882 initialization had ended, the superior machine and TNT4882 carry on the data transfer. The superior machine transmission counter uses for the byte count which checks between the superior machine and FIFO must transmit and receive. Counts the GPIB connection transmission by NTN4882 and the receive byte. And FIFO transmits a data every time in the superior machine, the superior machine connection then reduces the superior machine transmission counter transmission counting value one, and inquires the counting value whether to be equal to zero. If the counting value is equal to zero, the superior machine started to examine the termination condition, judged whether to finish. If finished, the data transfer completed; Otherwise, waiting.
Figure 4 TNT4882 and micro controller connection schematic diagram
3 TNT4882 in multi-channel program control power source’s application and software flow
The multi-channel program control power sources are for the aerospace electronic installation and system’s automatic test equipment (ATE) the technical requirement designs and the development, is present in the high performance aerospace self-test system one of essential supplementary equipment. Not only this program control power source’s output may satisfy present domestic, the overseas different power supply system’s technical requirement, moreover also the necessary output multi-channel accessory power supplies, satisfy the user the special need. Considers the multi-channel program control power source’s versatility, and is suitable for the international interface standard, adds a GPIB bus interface in the development, enables our multi-channel program control power source to use in the different control system. Multi-channel program control power source hardware chart as shown in Figure 3.
The multi-channel program control power sources by the data acquisition, the micro controller, the power source module, the GPIB bus interface and the superior machine are composed. The multi-channel program control power sources output simulation quantity after transformation delivers a/D switch to carry on the transformation, transforms the digital quantity to deliver micro controller processing, simultaneously the micro controller also gathers the switching signal. Micro controller after gathering signal processing, delivers through the GPIB main line to the superior machine, realizes the superior machine to the power source condition real-time monitoring; At the same time, the superior machine may through the GPIB main line transmission control command micro controller, realize the superior machine to the multi-channel program control power source’s program control.
3.1 TNT4882 and micro controller connections and programming
TNT4882 D0~D7 and 89C51 P0 mouth direct connected, ADDR0~ADDR5 is connected with micro controller’s address A0~A5, CS makes TNT4882 to select patches or strips of land as worth saving for seed the signal, with online programmable logical component docking. WR, RD and the micro controller read, with directly connected, reads and compares, writes the register to carry on reads, writes the operation. Because the TNT4882 interrupt is the high level, is opposite with at89C51 interrupt request polarity, therefore needs after reverse, only then may with the micro controller’s interrupt INT connection.
In this multi-channel program control electrical power system, has two crystal oscillators: Uses in producing the micro controller work clock, uses in producing the TNT4882 work clock. Figure 4 is TNT4882 and the micro controller’s connection schematic diagram.
Receives, sends the data subroutine with MCS51 assembly language compilation’s GPIB to see the network supplement version.
3.2 superior machine programming
Uses develops platform - - LabWindows/CVI face the instrument and observation process interactive C/C (C for Virtual Instrumentation) the language. It is one kind the C language platform and the observation specialized tool room organic synthesis development platform. It not only has the integration to develop the platform, the interactive programming method, the function kneading board and the storehouse function, moreover also has the simple intelligible friendly graph design contact surface, the consummation development system compatibility as well as the nimble program debugging method, established the data acquisition system, the measurement system, the examination and the process monitoring system for the familiar C/C language’s development personnel has provided the enormous convenience. Figure 5 is the superior machine control procedure flow chart.
The multi-channel program control power sources and a superior machine correspondence’s application procedure sees the network supplement version.
Conclusion
The new generation has the GPIB interface bus’s multi-channel program control power source, conforms to the IEEE-488.2 data interface standard. So long as with the standard GPIB interface cable and the system connection, may apply in nimbly any system, not factor and so on model limits, and has the very good extendibility, has demonstrated its unique superiority.
