Abstract:
An in-line programming (ILP) system and method for programming and testing programmable integrated circuit devices (PICs) and performing the assembly of printed circuit board assemblies (PCBAs). Printed circuit boards enter and leave the ILP system on a conveyor system. PICs are loaded into the ILP system, and the ILP system automatically programs and tests the PICs and places them onto the PCBs as the PCBs arrive on the conveyor. The programming and testing operations are performed by the same piece of equipment that performs the PCBA assembly operation.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is related to U.S. Provisional Patent Application Ser. No. 60/117,873, filed Jan. 29, 1999, entitled “IN-LINE PROGRAMMING DEVICE WITH SELF-TEACHING CAPABILITY,” the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to concurrent automated programming of programmable electronic devices, and more particularly to programming and testing multiple device types and patterns and performing circuit board assembly simultaneously in a single in-line programming device. 
     In the semiconductor industry, a considerable number of electronic devices such as programmable integrated circuit (PIC) devices are provided by vendors in programmable form with blank memories or unspecified connections between arrays of logic. Users can then custom configure or program the electronic devices to perform their intended finction by programming them, transferring or “burning in” a sequence of operating codes into the memory, or by specifying a particular arrangement of gating logic connections. 
     Numerous manufacturers have developed automated machinery for handling and programming such devices. Such machinery moves blank devices from a source medium (e.g., trays, tubes, tape) to one or more programming sites, carries out the programming operation on each device, and moves programmed devices from the programming sites to an output medium (e.g., trays, tubes, tape). Typical users of automated programming equipment are highly sensitive to system throughput, which is typically measured in correctly programmed devices per hour, and yield, which is typically defined as the percentage of devices which are correctly programmed. 
     Before any printed circuit board assembly (PCBA) containing a programmable integrated circuit (PIC) can be used, the PIC must be configured, or programmed, so that it may perform its intended function. During programming, a pattern is loaded into the unprogrammed PIC. These patterns may be changed from time to time as the requirements of the function of the PCBA change over time. Also, in some applications, the pattern may be individualized for each PCBA that is assembled. 
     For years, PICs have been programmed before being assembled onto a printed circuit board using a methodology called off-line programming (OLP). This, however, created some problems in that OLP of the PICs has to be performed prior to assembly. Specialized equipment must also be obtained to perform OLP. Further, OLP has to be scheduled, which may delay the manufacture of PCBAs and create scheduling problems and bottlenecks in the process. Moreover, once the PICs are programmed, they must be stored until the assembly process begins. This storage and related delay typically creates an inventory of programmed PICs. Not only does this inventory cost money, but in the event that a pattern change is required immediately, the inventory of programmed PICs may have to be destroyed, which adds to the cost and creates an additional delay before the assembly of more PCBAs can commence. 
     To solve these problems, a technique called in-circuit programming (ICP) was developed. ICP allows for a PIC to be programmed after it is placed on a printed circuit board, i.e., after the PCBA is assembled. Thus, the need for an inventory of programmed devices was eliminated, and individualized PICs no longer needed to be matched with the corresponding PCBA because all the PICs are identical (unprogrammed) at assembly time. 
     However, new problems arose. For example, because it is not feasible to program all PICs in circuit, the designers of the PCBA must choose only devices that are ICP compatible. ICP compatible PICs cost more than similar non-ICP compatible PICs in many cases, so the cost of the PCBA may be higher when using ICP. Additionally, the PCBA design may be more complex to accommodate ICP, so the time to market may be negatively impacted. Furthermore, specialized equipment is required, and software must be written, to perform the programming operation, which also may impact time to market for the PCBA. Since the programming operation may take a number of minutes to perform, a production line may be slowed down waiting for programming to complete. To address this throughput problem, some users may set up several ICP programming stations to service a single PCBA assembly line. However, this solution requires additional equipment, floor space in the factory and capital outlay. Additionally, if the application for the PCBA requires that the PICs be programmed with individualized patterns, it may be necessary to match the individual PICs with their corresponding individual PCBAs. This additional complication adds additional cost and complexity to the assembly operation. Finally, in the event that the PIC fails to program, the entire PCBA will have to be reworked to replace the PIC. 
     Accordingly, what is needed in the art is a system and methodology for programming PICs and assembling PCBAs without the drawbacks associated with the off-line programming and in-circuit programming techniques. 
     SUMMARY OF THE INVENTION 
     Briefly, the invention provides in-line programming techniques for programming and testing any combination of devices and patterns. The techniques of the present invention are useful for programming a variety of types of programmable integrated circuit devices (PICs), including for example, flash memories, EEPROMs, microcontrollers, PLDs, PALs, FPGAs and the like. According to the invention, an in-line programming (ILP) system programs and tests PICs and performs the assembly of printed circuit board assemblies (PCBAs). Printed circuit boards enter and leave the ILP system on a conveyor system. PICs are loaded into the ILP system, and the ILP system automatically programs and tests the PICs and places them onto the PCBs as the PCBs arrive on the conveyor. 
     The present invention addresses all of the above problems (e.g., costs, complications and delays) by performing the programming and testing operations with the same piece of equipment that performs the assembly operation. Using the techniques of the present invention, PICs are programmed on demand so the need for an inventory of programmed PICs is eliminated, and changes to the program pattern may be incorporated immediately without waste. Any PICs that fail to program are rejected by the ILP system so that bad PICs are never placed onto a PCBA. Because the PCBA does not have to be designed to accommodate an in-circuit programming technique, the PCBA designer is unconstrained in choice of PICs. The ILP system generally programs PICs faster than PICs can be programmed using the in-circuit programming methodology. The ILP system is also able to program a number of devices simultaneously, allowing a PCBA assembly line to produce PCBAs at a faster pace than that at which a single PIC can be programmed. Thus, an assembly line incorporating an ILP system may be smaller and produce PCBAs faster, with higher quality and less expense than an assembly line incorporating an in-circuit programming system. Further, the use of an ILP system in an assembly line allows for PCBAs to be produced less expensively than in an assembly line incorporating programmed PICs from an off-line programming system. 
     According to an aspect of the present invention, a method of automatically assembling a printed circuit board assembly (PCBA) in an assembly apparatus is provided. The method typically comprises the steps of a) receiving, in the assembly apparatus, a programmable electronic device to be programmed, and b) automatically programming the electronic device in the assembly apparatus. The method also typically includes the steps of c) receiving a printed circuit board in the assembly apparatus, and d) assembling the PCBA in the assembly apparatus by automatically placing the programmed electronic device on the printed circuit board so as to form the PCBA. 
     According to another aspect of the present invention, an assembly apparatus capable of automatically assembling a printed circuit board assembly (PCBA) is provided. The apparatus typically comprises a means for receiving, in the assembly apparatus, a programmable electronic device to be programmed, and a means for automatically programming the electronic device in the assembly apparatus. The apparatus also typically includes a means for receiving a printed circuit board in the assembly apparatus, and a means for automatically placing the programmed electronic device on the printed circuit board so as to form the PCBA. 
     Reference to the remaining portions of the specification, including the drawings and claims, will realize other features and advantages of the present invention. Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with respect to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a block diagram view of a surface mount production line including an inline programming system according to an embodiment of the present invention; 
     FIG. 2 illustrates a block diagram of an inline programming system according to an embodiment of the present invention; 
     FIGS. 3 a-b  illustrate a flow chart showing the general operation of the concurrent programming system according to an embodiment of the present invention; 
     FIGS. 4 a-c  illustrate a flow chart showing the general operation of the conveyor system according to an embodiment of the present invention; 
     FIG. 5 illustrates a flowchart showing the general operation of the pick and place system according to an embodiment of the present invention; and 
     FIG. 6 illustrates a flowchart showing the general operation of the central control unit according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a block diagram view of a surface mount production line  10  including an inline programming apparatus  20  according to an embodiment of the present invention. As shown, surface mount production line  10  includes a linear array of machines or components that perform unique functions. For example, component  30  may be a stencil printer machine  30  that controls the application of solder paste to a blank circuit board. Component  40  may be a chip shooter machine that performs high speed placement of devices and circuit elements that do not require a high level of placement accuracy. Such devices and elements include resistors, capacitors, and the like. Component  50  may be a fine pitch placement machine that places devices at low speed with extreme accuracy. Component  60  may be a reflow oven that “cooks” the solder paste, thereby soldering to the board all the devices and elements that were placed on the board by the previous machines. Each component of production line  10  includes a printed circuit board conveyor for moving printed circuit boards within each machine. The conveyors within each component interface physically and electrically to form one continuous conveyor that allows circuit boards to flow from one end of the line to the other. Circuit boards typically pause within each machine and are locked in place by the conveyor, e.g., using a clamping mechanism, while being subjected to the particular processing that machine is designed to perform. 
     FIG. 2 illustrates a block diagram of an inline programming apparatus  20  according to an embodiment of the present invention. Inline programming apparatus  20  receives and programs blank programmable devices and places the programmed devices on printed circuit boards as they pass through the apparatus on the conveyor. According to an embodiment of the present invention, the operation of in-line programming apparatus  20  relies on four parallel asynchronous processes. In one embodiment, these processes are embodied in four different components of in-line programming apparatus  20 : the concurrent programming subsystem  100 , the conveyor subsystem  110 , the pick and place subsystem  120 , and the central control unit  130 . Each component depends on input signals representing events from the other systems. The interdependencies are described in the flow charts illustrated in FIGS. 3-6 as described in more detail below. 
     Control unit  130  provides overall coordination and control of the various subsystems. Typically, control unit  130  communicates with the various subsystems, and with the upstream and downstream machines in some cases, through one or more busses  150  by sending and receiving control and status signals. Although not shown, each subsystem includes a processor component for controlling functions of the subsystem, and for effecting communication with control unit  130  and with the other subsystems. 
     Conveyor subsystem  110  receives printed circuit boards from the upstream machine (e.g., fine pitch placement machine  50 ), moves the board through apparatus  20  and delivers a printed circuit board to the downstream device (e.g., reflow oven  60 ). Conveyor subsystem  110  includes sensors  112  and  114  as are known in the art for detecting when a board has been received and delivered, respectively. For example, each sensor  112  and  114  detects a trailing edge of the board and signals conveyor subsystem  110  and/or control unit  130 . A third sensor (not shown) is also provided just upstream from a processing station location  116  of conveyor subsystem  100 . 
     Device input interface  140  is provided for receiving devices to be programmed from outside of system  20 . In one embodiment, device input interface  140  includes a device tray shuttle for receiving a tray holding one or more devices. Other device delivery interfaces may be used as are well known, including interfaces capable of receiving device holding media such as tape, tubes and the like. Pick and place subsystem  120  includes a pick and place head  122  that is capable of picking up the required programmable devices. Pick and place subsystem  120  typically includes tracks or rails  118   a  and  118   b , along which a portion of subsystem  120  is able to move so as to effect movement of head  122  for picking and placing devices within apparatus  20 . 
     Concurrent programming subsystem  100  is responsible for programming devices with the desired program pattern and for testing the programmed devices prior to placement on a printed circuit board. In one embodiment, concurrent programming subsystem  100  includes multiple sites  102   1  to  102   N  for concurrently programming and testing multiple devices. An example of such a concurrent programming system can be found in U.S. Pat. No. 5,996,004, assigned to BP Microsystems, Inc., entitled “Concurrent Programming Apparatus and Method for Electronic Devices,” the contents of which are hereby incorporated by reference for all purposes. “Programming” a device typically includes transferring or “burning in” a sequence of operating codes into the memory, or by specifying a particular arrangement of gating logic connections (e.g., for a programmable logic array device). 
     During operation, each programming site of concurrent programming subsystem  100  moves through the following states: EMPTY, WAITING, ACTIVE, READY, and PROMISED. EMPTY indicates that the programming site, or socket, is physically empty. WAITING indicates that the socket is waiting for the pick and place subsystem  120  to deliver a device to be programmed. ACTIVE indicates that a device is in the socket and is being programmed. READY indicates that the socket contains a programmed device. PROMISED indicates that the socket contains a programmed device that has been “promised” to conveyor subsubsystem  110  for assembly. 
     Once programming subsystem  100  has been configured for all programmable devices required by the boards to be processed, it is ordered by central control unit  130  to enter its processing loop, for example, as shown in FIGS. 3 a-b . FIGS. 3 a-b  illustrate a flow chart showing the general operation of concurrent programming subsystem  100  according to an embodiment of the present invention. Concurrent programming subsystem  100  operates by running a loop that repeats continuously until the job is over (i.e., programming of all devices is completed). Initially, for each programming site, the system determines whether the site is in the EMPTY state in step  200 . If the site is EMPTY, that site is transitioned to the WAITING state in step  205 . Concurrent programming subsystem  100  then asks pick and place subsystem  120  to deliver a device to the specific site in step  210 . (The “A” in step  120  indicates that data is provided to pick and place subsystem  120 , e.g., data indicating the locations at which to pick up and to place the device as well as a status variable.) If the site is not EMPTY, in step  220  it is determined whether the site is in the WAITING state. If the site is not WAITING, the process proceeds to step  240 . Otherwise, in step  225  it is determined whether a device has been delivered. If the site is WAITING, and a device has been delivered, device programming is initiated in step  230 , and the site is transitioned to the ACTIVE state in step  235 . 
     In step  240 , it is determined whether the site is in the ACTIVE state. If the site is ACTIVE, it is determined whether the site has finished programming the device, and optionally whether the programmed device has been successfully tested (e.g., by applying voltages and waveforms to the programmed device) in step  245 . If a device fails testing, the device is discarded and a new device is provided to concurrent programming subsystem  100 . If programming has finished, the site is transitioned to the READY state in step  250 . In step  255  the system determines whether the site is in the PROMISED state. If the site is PROMISED, concurrent programming subsystem  100  queries pick and place subsystem  120  to determine whether the device has been removed from the site in step  260 . (The “B” in step  260  indicates that data is provided to and from pick and place subsystem  120 .) If the programmed device has been removed, the site is transitioned to the EMPTY state in step  265 . 
     In step  270 , it is determined whether all sites have been checked. If all sites have not been checked, the process returns to beginning step  200  for the next site. If all sites have been checked, the process proceeds to step  275 . With reference to FIG. 3 b,  in step  275 , concurrent programming subsystem  100  determines whether central control unit  130  is requesting a device location (e.g., identification of any site handling the programming for a specific device type). (The “C” in step  275  indicates that data is provided to and from central control unit  130 .) If central control unit  130  is not requesting a device location, the process proceeds to step  200 . If central control unit  130  is requesting a device location, it is determined in step  280  whether any site handling the specific requested device type is in the READY state. If no site handling the specified device type is READY, in step  295 , concurrent programming subsystem  100  provides a message to conveyor  110  indicating that no device is ready. The message may be provided directly to conveyor  110 , or it may be relayed first to central control unit  130 . The process then loops back to beginning step  200 . If a site handling the specified device type is READY, the site is transitioned to the PROMISED state in step  285 , and the location of that site&#39;s socket is provided to conveyor  110 . (The “C”s in steps  290  and  295  indicate that data is provided to conveyor  110  either directly or through central control unit  130 .) The process then loops back to beginning step  200 . 
     Conveyor subsystem  110  interacts with the upstream machine to bring printed circuit boards into ILP system  20 . Conveyor subsystem  110  also interacts with the downstream machine to provide a printed circuit board assembly thereto. For example, as shown in FIG. 1, the conveyor system of inline programming system  20  interacts with the fine pitch placement machine  50  (i.e., upstream machine) to receive a printed circuit board to be processed, and with reflow oven  60  (i.e., downstream machine) to deliver a processed printed circuit board assembly thereto. Conveyor subsystem  110  also interfaces with central control unit  130 , concurrent programming subsystem  100  and pick and place subsystem  120 . In one embodiment, conveyor  110  uses four defined state variables to interact with the upstream and downstream machines: READY, AVAILABLE, UPAVAIL and DOWNREADY as it moves through its states of operation. In one embodiment, these state variables are binary variables having two states. The status variables are communicated between conveyor subsystem  110  and the upstream and downstream machines through the electrical connections provided between ILP system  10  and the upstream and downstream machines. Once conveyor subsystem  100  has been configured with velocity and acceleration limits, it is ordered by central control unit  130  to enter its processing loop to await the first board to be delivered. One example of such a processing loop is shown in FIGS. 4 a-c.    
     In one embodiment, with reference to FIGS. 4 a-c,  conveyor subsystem  110  has six defined states of operation as follows: 
     State 0: In this state, the conveyor is waiting, for the upstream machine to indicate that a board is ready for delivery. The conveyor is preferably stationary to avoid unnecessary wear and tear on the belt and other mechanical components. In step  300 , READY is set to one state, e.g., low, to indicate that conveyor  110  is not ready to receive a board from the upstream machine, and AVAILABLE is set to one state, e.g., low, to indicate that conveyor  110  is not ready to deliver a printed circuit board assembly to the downstream machine. Conveyor  110  transitions in step  305  from state 0 to state 1 when the upstream machine sets UPAVAIL to one state, e.g., high, to indicate that it is ready to deliver a printed circuit board. 
     State 1: In this state, conveyor  110  is waiting to receive the board from the upstream machine. Conveyor  110  will match the speed of the conveyor on the upstream machine to allow a smooth transfer from one machine to the next. In step  310 , READY is set high to indicate that conveyor  110  is ready to receive a printed circuit board. Conveyor  110  transitions from state 1 to state 2 in step  320  when the trailing edge of the board is detected by entry sensor  112 . 
     State 2: In this state, conveyor  110  “owns” the board and may move the board as quickly as possible to the processing station location  116 . A clamping mechanism is provided in one embodiment for clamping, or holding, the device in place at processing station location  116 . In one embodiment, velocity and acceleration limits for conveyor  110  are preset by the system operator. In step  325 , READY is set low to prevent the upstream machine from sending another board before the current board has finished processing. Once the board is at the processing station, in step  330 , conveyor  110  stops moving and a clamp is activated to hold the board in place during processing. In step  335 , central control unit  130  is notified by conveyor  110  that the board is ready for processing, and conveyor  110  transitions from state 2 to state 3. (The “D” in step  335  indicates that data is provided to central control unit  130 .) 
     State 3: In this state, conveyor  110  is waiting for central control unit  130  to indicate that the processing of the board is completed. In step  340 , conveyor  110  transitions from state 3 to state 4 when central control unit  130  indicates that the board is finished processing. (The “E” in step  340  indicates that data is provided to and from central control unit  130 .) Processing is complete when all required programmed devices have been placed on the printed circuit board. Generally, one or more programmed devices are required for each printed circuit board assembly. 
     State 4: In this state, the assembled board is unclamped and conveyor  110  moves it as quickly as possible to the exit location (e.g., interface with downstream machine). In step  345 , AVAILABLE is set high to indicate that conveyor  110  is ready to deliver an assembled board to the downstream machine. In step  350 , the board is unclamped and moved toward the exit. In step  355 , conveyor  110  stops movement until it is determined that the downstream machine is ready to receive the board in step  360 . Conveyor  110  transitions from state 4 to state 5 when the downstream machine sets DOWNREADY to one state, e.g., high, to indicate that it is ready to receive a printed circuit board assembly. 
     State 5: In this state, in step  365 , conveyor  110  matches the speed of the conveyor on the downstream machine to provide a smooth transfer from one machine to the next. Conveyor  110  remains in motion until, e.g., the trailing edge of the board is detected by exit sensor  114  in step  370 . When the board has left conveyor  110 , AVAILABLE is set low, and conveyor  110  stops motion and transitions from state 5 to state 0 (step  300 ) to wait for the next board to be processed from the upstream machine. 
     Pick and place subsystem  120  provides the ability to move devices from one location to another within the ILP system. In one embodiment, pick and place subsystem  120  includes self-teaching capability for determining the precise locations at which to pick and place devices. An example of such a pick and place system can be found in U.S. patent application Ser. No. 09/361,791 filed Jul. 27, 1999, entitled “Pick and Place Teaching Method and Apparatus for Implementing the Same,” the contents of which are hereby incorporated by reference for all purposes. 
     Pick and place subsystem  120  services requests from concurrent programming subsystem  100  and conveyor  110  to move devices from one location to another. These requests may be received directly from concurrent programming subsystem  100  and conveyor  110 , or through central control unit  130 . The system making the request will provide the location from which to pick up a device, the location at which to place the device, and the address of a status variable. As one example, pick and place subsystem  120  can be directed to pick up an unprogrammed device, e.g., from a tray of unprogrammed devices, and place the device in a specific site&#39;s socket of concurrent programming subsystem  100  for processing. Blank devices may be provided to inline-programming apparatus  20  via device input interface  140  using a variety of media, including trays, tubes and tape as is well known. As another example, pick and place subsystem  120  can be directed to pick up a programmed device from concurrent programming subsystem  100  and place the programmed device on a printed circuit board at a specific location on conveyor  110 . Pick and place subsystem  110  queues the requests and services them as soon as possible. The caller can monitor the status variable for the following states: Not yet ready, Underway, Finished successfully, and Finished with an error. Pick and place subsystem  110  performs one move after another until the job is completed. If the queue becomes empty, pick and place subsystem  110  will wait idly until another request is made. The operation of pick and place subsystem  110  is described in more detail with reference to FIG.  5 . 
     FIG. 5 illustrate a flowchart showing the general operation of pick and place subsystem  110  according to an embodiment of the present invention. In step  400 , pick and place subsystem  120  determines whether a request is received from concurrent programming subsystem  100  or from conveyor subsystem  110  to pick and place a device. (The “A” in step  400  indicates that data is provided to pick and place subsystem  120 .) The entity requesting that a device be brought to it calls pick and place subsystem  120  and provides the location and status address information. If such a request is received, in step  410 , the system places the location information and the associated status variable address in a queue and proceeds to step  430 . In one embodiment, the queue is implemented in a memory, such as a FIFO buffer. If no request is received, pick and place subsystem  120  checks to see whether any data is stored in the queue. If data is stored in the queue the process proceeds to step  430 , and if no data is stored in the queue, the process loops back to beginning step  400 . 
     In step  430 , pick and place subsystem  120  reads the data in the queue having the highest priority, and proceeds to pick and place the requested part at the specified locations. In step  440 , the system determines whether any status requests have been made. (The “B” in step  440  indicates that a request is provided to pick and place subsystem  120 .) If status variables are requested, the system provides them to the requesting entity in step  450 . The process then loops back to beginning step  400 . 
     Central control unit  130  coordinates the action of the other system components as described in more detail below. Central control unit  130  is preferably implemented as an industry standard Pentium-based personal computer executing the Microsoft Windows operating system, although any other processor and any other operating system may be used as desired. As part of its function, central control unit  130  coordinates the delivery of unprogrammed devices to concurrent programming subsystem  100  for programming, as well as the placement of programmed devices on the circuit boards. The operation of the central control unit is described in more detail with reference to FIG.  6 . 
     FIG. 6 illustrates a flowchart showing the general operation of central control unit  130  controlling the operation of placing programmed devices on a printed circuit board according to an embodiment of the present invention. In step  500 , central control unit  130  checks whether conveyor  110  has indicated that a board in locked in place and ready for processing. (The “D” in step  500  indicates that data is provided to and from central control unit  130 .) If a board is locked in place, in step  510  fiducial recognition techniques are used to identify the locations at which one or more programmed devices should be placed. In general, the boards will not be clamped in precisely the same locations in station location  116 . Once clamped down, the board will not move, but the clamped positions will vary slightly from board to board. In one embodiment, a camera is used to detect the location of a pair of “fiducial marks”, e.g., small circles or cross marks on the board to determine the location and orientation of the board. This location information is used in conjunction with the known board location(s) (e.g., where the device(s) are to be placed on the board), by the pick and place subsystem  120  to compute the exact location, and orientation, at which to place a device on the board. In step  520 , control unit  130  queries concurrent programming subsystem  100  for the location of a programmed device. (The “C” in step  520  indicates that data is provided to and from central control unit  130 .) If the location is valid, the process proceeds to step  530 . If not, the process loops back (indicated by the “ 8 ”) and queries the concurrent programming subsystem  100  for a device location. 
     In step  530 , central control unit  130  instructs pick and place subsystem  120  to pick and place the device identified by concurrent programming system in step  520 . (The “A” in step  530  indicates that location and status data is provided to and from pick and place subsystem  120 .) After the device has been placed on the board, the specific location is marked as PLACED. In step  550 , the unit determines whether all devices required to be placed on the board have been placed thereon. If not, the process loops back (indicated by the “ 8 ”) to step  520  where the central control unit queries concurrent programming subsystem  100  for the location of the next device to be placed. If all devices have been placed, in step  560 , central control unit  130  notifies conveyor subsystem  110  that the board has been processed and can be moved on. (The “E” in step  530  indicates that data is provided to and from conveyor subsystem  110 .) In step  570 , central control unit waits until conveyor subsystem  110  acknowledges that the board has been processed and then reverts back to beginning step  500  to coordinate processing for the next board. 
     According to one embodiment, in-line programming apparatus, and all of its components are operator configurable using computer code run on central control unit  130 . Computer code for operating and configuring all components of in-line programming apparatus as described herein is preferably stored on a hard disk coupled to central control unit. The entire program code, or portions thereof, may also be stored in any other memory device such as a ROM or RAM, or provided on any media capable of storing program code, such as a compact disk medium, a floppy disk, or the like. 
     While the invention has been described by way of example and in terms of the specific embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.