Bidirectional port

Bidirectional ports work in two directions and provide, in addition to data retrieval, semiautomated or fnlly antomated control of the instrnment. 

With unidirectional ports the instrnment leads the processing of data, and the data management system waits for information from the instrnment. Unidirectional ports do not attempt to control the instrnment software. The most sophisticated solution is to connect directly to an instrnment nsing a bidirectional port. In this case work lists or single measnrement orders are compiled by the data management software during the rontine workflow and measnrements are triggered directly. 

HDL Design Wizard is a GUI tool to help the designers visually declare the interfaces of an HDL module (in Verilog) and entity (in VHDL). Input, output or bidirectional ports are defined. 

DC analyzes any timing path by breaking up the path into a head-to-tail sequence of individual arcs. Hence it considers the path from the latch through the bidirectional cell back to the latch. One must use path segmentation by specifying setjnput delay and set output delay commands. A set output delay or a setjnput delay command at the output of the three-state cell driving the bidirectional port breaks the timing arcs at that point. A set output delay command at an internal pin creates a valid endpoint and a setjnput delay creates a valid start-point. 

Bi-directionals are also treated as three-state nets by TC. Hence, the insertion of disabling logic would occur for bi-directionals unless the -no disable option is used. Bidirectional ports, by default, are always configured in the output mode during test. There are options available with the set scan configuration command to specify the direction of the bi-directional ports during scan shift. 

Figure 8.5 shows a design with a functional path from the bidirectional port C to registers. 

In this section, we summarize the entire test synthesis flow by means of an example. Example 8.2 outlines the methodology to be followed for a design with bidirectional ports, three-state O/P ports, I/P and O/P ports. We illustrate the entire flow ranging from synthesis to test insertion, and JTAG synthesis followed by pad synthesis (assuming of course, that the ASIC vendor library supports that). 

You are using LSI Logic as your ASIC vendor. How is Test Compiler s default test protocol different from that of LSI Logic in terms of handling bidirectional ports ... 

LSI Logic has a four cycle test application sequence which imposes certain requirements on bidirectionals and their mode in each cycle. All bidirectional ports must be in the input mode in cycles 1,3 and 4. This is accomplished by activating the bidirectional output inhibit signal in the cycles 1,3 and 4. This signal that controls the direction of the bidirectional ports needs to be a primary input port and must have the sIgnaLtype attribute test bidir controlUnverted] in TC. 

In cycle 2, the bidirectional output inhibit signal is not active and hence the ATPG interprets the direction of the bidirectional ports in this cycle. 

The bidirectional output inhibit input port is active and all the bidirectional ports are inputs. 

In this cycle the output inhibit port is inactive. LSI has bidirectional pads with pins TN and EN. TN is the pin to which the bidirectional output inhibit signal is connected to. When TN is active or 1, the bidirectional is in the input mode. When TN is inactive or 0, ATPG configures the bidirectional port direction through EN. 

The key part of the system is the multiport valve, which interconnects the different parts and solutions used by the system. The common port is connected to a reversible pump with the retention coil placed in between. The pump is connected to the carrier solution reservoir. The common port can access any of the other ports, which lead to sample, standard solutions or reagents, mixing chamber and sensor array, by electrical rotation of the valve. Since the system is bidirectional, volumes can not only be propelled directly to the detector, but also be injected into the retention coil, therefore merging accurate aliquots of different solutions. In order to assure proper mixing of the solutions not only via diffusion... 

The TMS320C30 [Papamichalis and Simar, 1988] follows the basic architecture of the TMS-320 series. Unlike the DSP-32, it uses pipeline interlocks. Like the DSP-32, it features its own internal format for floating point numbers. Because of the four stage pipeline organization, it can perform a number of operations in parallel. It also features a delayed branch - something of a novelty in DSP processors. The TMS320C40 [Simar et al., 1992] has six parallel bidirectional I/O ports controlled by DMA on top of the basic TMS-320C30 architecture. These ports have been used for multiprocessor communication. 

As their names suggest, terminal servers and print servers support the use of terminals and printers on networks. They support modems and other devices as well. The primary difference between them is that terminal servers are bidirectional devices while print servers have been unidirectional devices, at least as far as data transmissions are concerned. Unlike transceivers, repeaters, or port multipliers, terminal servers and print servers are intelligent devices which have their own network addresses and perform more than just a physical connection or signal forwarding function. 

Obviously, this port is bidirectional—data can flow both in and out with equal ease. The signal format used to exchange data serially over the six lines provided through this port is unique to Commodore. The format should not be confused with the more standard RS-232 serial communications format used by numerous peripherals RS-232 communication is handled through the user port (see below). The serial port is essentially a stripped-down version of the parallel IEEE-488 port used for most data communications in Commodore s earlier PET/CBM models. As the term serial implies, data can be transferred only one bit at a time (and in only one direction at a time, either in or out). Three of the other lines control the direction of data flow, and whether the signals on the data line are to be interpreted as data or as commands to the peripheral device. The computer s RESET line is also present at this port, which explains why the disk drive resets whenever the computer is turned on or off. 

The most common use of the parallel interface is printer communication, and there are three major types standard, bidirectional, and enhanced parallel ports. Let s look at the differences between the three. 

As its name suggests, the bidirectional parallel port has one important advantage over standard parallel ports it can both transmit and receive data. These parallel ports are capable of interfacing with devices like external CD-ROM drives and external parallel port backup drives (Zip, Jaz, and tape drives). Most computers made since 1994 have a bidirectional parallel port. 

There are two implementations of IEEE 1284, ECP parallel ports and EPP parallel ports. An Enhanced Capabilities Port (ECP port) was designed to transfer data at high speeds to printers. It uses a DMA channel and a buffer to increase printing performance. An Enhanced Parallel Port (EPP port) increases bidirectional throughput from 150KBps to anywhere from hOOKBps to 1.5MBps. 

B, C, D. Bidirectional parallel port can both transmit and receive data. An ECP was designed to transfer data at high speeds. EPP parallel ports provide for greater transfer speeds and the ability to send memory addresses as well as data through a parallel port. 

They usually use a COM port or bidirectional parallel port instead of SCSI to transfer their data. They are limited in their quality, however, and generally should not be used in graphics work. 

Printer parallel port—Uni., bidirectional, disable/enable, ECP, EPP... 

In LNT, gates are bidirectional. So we can present all AADL port directions in, out and in out. The correspondence between in/out ports is ensured with identifiers, every connection (from out to in port) has an identifier. Sender includes a list of connection identifiers in its output. has a list of accepted connection identifiers (parameter ConnectIDs) to verify if its is concerned by the received input. Thus, we can specify all AADL connection topologies. The Example presented in listings 1.3 and 1.4 transforms Producer/Consumer communication Producer provides inputs to two consumers Consumerl and Consumer2. This is an 1-to-n topology and event data type AADL port connection. In LNT, we get five processes. Process Producer sends messages. Each EventPort ConnPC identifies its concerned inputs with identifiers Producer D Consumer D. 

This occurs because the S3mthesizer does not see a JK flip flop in the process function but knows, from the clock condition in the Wait statement, that a sequential circuit is being inferred. As discussed in section 5.1.3, the choice of flip flop in an inferred sequential section is left entirely up to the synthesizer. It will therefore tend to select a simple one rather than a complex one, and so not risk the overspedfication of the circuit. Observe the feedback of S, which is required to determine the next state of the circuit. Because this signal is not only updated and output by the process but also read, the connection to the top level of the drcuit is defined in the schematic as bidirectional. This does not mean that it can be used as an input to the circuit as the entity declaration for this component states that the port Q, to which it is directly connected, is of mode output. 

To combat die problem of the same seed always generating the same pseudorandom sequence, the design in Figure 7.16b can be loaded with a new seed. Externally, the structure looks identical to the drcuit in Figure 7.16a The key difference in this case is that the output ports for the bit pattern are now bidirectional as they are used to load the new seed. This has significant consequences for fhe way in which these ports are designed as the drcuit cannot drive the external lines when a new seed is being loaded. 

STATUS port), and 4 four bidirectional leads (CONTROL port), thus providing a simple means of using the PC interrupt structure. The remaining 8 pins are grounded. 

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