Abstract:
A method of programming and testing a microcontroller includes providing a connector having a plurality of ports on the circuit board containing the microcontroller, and providing programming data to a first one or more of the ports. Each of the first one or more of the ports is in electronic communication with a respective one of a first one or more of the pins of the microcontroller. The method further includes causing the microcontroller to provide selected diagnostic data on a second one or more of the pins, wherein each of the second one or more of the pins is in electronic communication with a respective one of a second one or more of the ports, receiving the selected diagnostic data from the second one or more of the ports and converting at least a portion of the received selected diagnostic data into one or more analog signals.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to the programming of microcontrollers, and in particular to a method of utilizing a single connector to perform both programming and diagnostic functions for a microcontroller.  
         [0003]     2. Description of the Prior Art  
         [0004]     As is known in the art, many current devices are controlled internally by a special purpose computer system known as an embedded system. Embedded systems generally use microcontrollers that contain many elements of a computer, such as a central processing unit, memory (RAM and ROM) and I/O, on a single chip or device. Most modern microcontrollers include flash memory, which is a form of non-volatile storage that can be electrically erased and reprogrammed so that software for the microcontroller can be readily stored, booted, and rewritten as necessary. One advantage of flash memory is that it can be erased and reprogrammed at signal levels normally found inside the microcontroller, and therefore flash memory can be reprogrammed without removing the microcontroller from the device of which it is a part (so called “in-circuit” reprogramming).  
         [0005]     Generally, embedded system development involves two basic functional steps, namely a programming step wherein software to be executed by the microcontroller for controlling various aspects of the device in question is written and loaded into the flash memory, and a diagnostic step wherein the functionality of the loaded software is evaluated and tested. Furthermore, these steps are typically repeated iteratively a number of times until the desired level of functionality of the system is achieved.  
         [0006]     As is known, microcontrollers include a number of pins for making electrical connections thereto. The programming of a microcontroller is normally facilitated by way of a connector that is provided on the circuit board containing the microcontroller. The connector has, at one end, a number of pins having leads connected thereto. The leads are in turn connected to the various pins of the microcontroller. At the opposite end, the connector has a number of ports, each port being connected to a respective one of the pins. The ports enable external connections to be made to the connecter (and ultimately the pins of the microcontroller through the leads connected to the connector), such as connections from a microcontroller programming tool, a number of which are known and commercially available.  
         [0007]     Diagnostic functions, on the other hand, are currently typically performed through the use of one or more external “daughter” boards that implement the diagnostic functionality. This approach, while effective, is disadvantageous, as it requires one or more additional connectors to be added to the circuit board containing the microcontroller to interface with the external “daughter” board or boards. These additional connectors add expense and occupy valuable circuit board space.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention relates to a method of programming and testing a microcontroller that utilizes a single connector for both programming and diagnostic functions. The microcontroller is provided on a circuit board and has a plurality of pins. The method includes providing a connector having a plurality of ports on the circuit board, and providing programming data used for programming the microcontroller to a first one or more of the ports. Each of the first one or more of the ports is in electronic communication with a respective one of a first one or more of the pins such that the programming data is provided to the microcontroller. The method further includes causing the microcontroller to provide selected diagnostic data on a second one or more of the pins, wherein each of the second one or more of the pins is in electronic communication with a respective one of a second one or more of the ports, receiving the selected diagnostic data from the second one or more of the ports and converting at least a portion of the received selected diagnostic data into one or more analog signals. Preferably, the receiving step comprises receiving the selected diagnostic data from the second one or more of the ports at a digital-to-analog converter, which converts the selected diagnostic data into analog form. The method also preferably includes outputting the one or more analog signals, such as with a display or printer, so that they may be analyzed by a developer.  
         [0009]     In one embodiment, the ports and pins associated with the programming related data are different than the ports and pins associated with the diagnostic related data. In another embodiment, one or more of the ports and pins associated with the programming related data are the same as one or more of the ports and pins associated with the diagnostic related data. The programming data may include one or more of program code data, clock data, programming and power voltages and/or ground signals in various combinations. In addition, the diagnostic data may include one or more of selected data relating to operation of said microcontroller, clock data, chip select data, and power and ground signals in various combinations. Finally, the method may further include causing the microcontroller to provide selected digital operational data on other pins and ports for analysis by a developer. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:  
         [0011]      FIG. 1  is a schematic diagram of a configuration for operating in a programming mode according to the present invention in which software may be programmed into a microcontroller; and  
         [0012]      FIG. 2  is a schematic diagram of a configuration for operating in a diagnostic mode according to the present invention in which software programmed into a microcontroller may be evaluated and tested. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]      FIGS. 1 and 2  are schematic diagrams of a system implementing the method of performing programming and diagnostic functions for a microcontroller according to the present invention.  FIG. 1  illustrates a configuration for operating in a programming mode according to the present invention, and  FIG. 2  illustrates a configuration for operating in a diagnostic mode according to the present invention.  
         [0014]     As seen in  FIG. 1 , a circuit board  5  is provided that includes a microcontroller  10 , which may be any type of microcontroller such as, for example, a microcontroller from the PICmicro® family of microcontrollers sold by Microchip Technology Inc. of Chandler Arizona. Microcontroller  10  includes a number of pins, including pins  12 ,  14 ,  16 ,  18 , 20 , 22 , 24  and  26  which are shown in  FIG. 1 . Circuit board  5  also includes connector  30  having a number of I/O ports numbered  1  through  8  in  FIG. 1  and a number of pins  32 ,  34 ,  36 ,  38 ,  40 ,  42 ,  44  and  46 , each electrically connected to a respective one of the ports  1  through  8 . As will be appreciated, in the case of each port  1  through  8  and corresponding pin  32  through  46 , a first lead or wire may be electrically connected to the port and a corresponding lead or wire may be electrically connected to the corresponding pin such that the two leads or wires are electrically connected to one another. Connector  30  may be any type of known on-board electrical connector, such as, without limitation, an 8-pin type FH21 connector sold by Hirose Electric, a Japanese company with United States headquarters located in Simi Valley, Calif.  
         [0015]     A programming tool  35 , such as, without limitation, the MPLab PM3 Universal Device Programmer sold by Microchip Technology Inc. of Chandler Arizona, is also provided as seen in  FIG. 2 . Programming tool  35  is adapted to be connected to various pins of the microcontroller  10  through connector  30  as described below for purposes of programming microcontroller  10 , i.e., loading it with desired software, while microcontroller  10  is connected to circuit board  5 .  
         [0016]     Pin  12  of microcontroller  10  is adapted to receive a supply voltage (+5V) for powering microcontroller  10 , pin  14  of microcontroller  10  is adapted to receive a ground signal, pin  16  (Prog-VPP) of microcontroller  10  is adapted to receive a voltage required for programming microcontroller  10 , pin  18  (Prog-Data) of microcontroller  10  is adapted to receive the serial data used for programming microcontroller  10  (program code data), and pin  20  (Prog-CLK) of microcontroller  10  is adapted to receive a clock signal used for programming microcontroller  10 . As seen in  FIG. 1 , the signals (+5V power supply, ground, programming voltage, serial programming code data and clock) for pins  12 ,  14 ,  16   18  and  20  are provided by programming tool  35  through ports  1 ,  2 ,  3 , 4 , and  5  of connector  30 , respectively, by way of wires  40  that connect output ports of programming tool  35  to ports  1  through  5  and by way of leads  45  that connect pins  32 ,  34 ,  36 ,  38  and  40  of connector  30  to pins  12 ,  14 ,  16 ,  18  and  20  of microcontroller  10 . Thus, the configuration shown in  FIG. 1  may be used to selectively program microcontroller  10  “in circuit.” 
         [0017]     Pins  22 ,  24  and  26  of microcontroller  10  are I/O pins provided as part of microcontroller  10 , such as serial peripheral interface (SPI) pins, and are connected to pins  42 ,  44  and  46 , respectively, of connector  30  by leads  45 . Pins  22 ,  24  and  26  are not used in the programming mode of the present invention, but instead are used during the diagnostic mode as described below. As a result, as seen in  FIG. 1 , ports  6 ,  7  and  8  do not have electrical connections thereto in the programming mode.  
         [0018]      FIG. 2  illustrates a configuration for operating in a diagnostic mode according to the present invention in which the software programmed into microcontroller  10  may be evaluated and tested. As seen in  FIG. 2 , programming tool  35  is no longer used, and instead a digital-to-analog converter  50  such as, without limitation, a 10-bit, 4 channel digital-to-analog converter, is provided. In the configuration of  FIG. 2 , pin  12  is connected to digital-to-analog converter  50  through pin  32  and port  1  of connector  30  to provide a power supply voltage (from the same source that is powering microcontroller  10 ) to digital-to-analog converter  50 , and pin  14  is connected to digital-to-analog converter  50  through pin  34  and port  2  of connector  30  to provide a ground signal (the same ground signal reference level utilized by microcontroller  10 ) to digital-to-analog converter  50 . In addition, according to an aspect of the present invention, microcontroller  10  is programmed to output through pin  24  selected data of interest relating to the operation of microcontroller  10  (in particular, selected data relating to various aspects of the operational functions that have been programmed into microcontroller  10  during the programming mode shown in  FIG. 1 ) and to output through pin  22  a clock signal. In the embodiment shown in  FIG. 2 , the selected data is output through pin  24  in a serial manner, but it will be appreciated that this is not required. The data signal from pin  24  is provided to a serial data input port of digital-to-analog converter  50  through pin  44  and port  7  of connector  30  via a lead  45  and a wire  40 . Similarly, the clock signal from pin  22  is provided to a serial clock input port of digital-to-analog converter  50  through pin  42  and port  6  of connector  30  via a lead  45  and a wire  40 . The microcontroller  10  is programmed to provide the data signal on pin  24  and the clock signal on pin  22  according to the particular serial data protocol of the digital-to-analog converter  50 . In the case of a multi-channel digital-to-analog converter  50 , the microcontroller  10  may also be programmed to instruct the digital-to-analog converter  50  to output selected portions of the data contained in the data signal provided on pin  24  on particular channels. For example, microcontroller  10  may be programmed to include certain current related data, certain voltage related data, and certain other data from a particular register within microcontroller  10  in the data signal provided on pin  24 , in which case microcontroller  10  may be further programmed to instruct the digital-to-analog converter  50  to output the current data on channel  1 , the voltage data on channel  2 , and the register data on channel  3  of the digital-to-analog converter  50 . The serial data protocol of the digital-to-analog converter  50  will enable each type of data in the serial data stream (e.g., the current data, the voltage data, etc.) to be identified with respect to one another. In addition, microcontroller  10  is programmed to output a chip select signal on pin  26 , which is provided to the digital-to-analog converter  50  through pin  46  and port  8 . The chip select signal indicates to the digital-to-analog converter  50  that serial data is coming from pins  22  and  24 .  
         [0019]     Once received by the digital-to-analog converter  50 , the data is converted to analog form and provided to an output device  55 , such as a display or a printer, where it may be viewed by a developer. The analog representation of the data allows a developer to view the values of various registers within microcontroller  10  in real time. As such, the configuration shown in  FIG. 2  creates a form of virtual oscilloscope that may be used for microcontroller software development.  
         [0020]     As seen in  FIG. 2 , a signal from pin  16  of microcontroller  10  is not used during the diagnostic mode, and thus port  3  of connector  30  does not have an electrical connection thereto. In addition, in the embodiment shown in  FIG. 2 , pins  18  and  20  of microcontroller  10 , normally used for receiving programming data and clock data during the programming mode, are not used to send data to digital-to-analog converter  50 . Thus, according to an aspect of the present invention, microcontroller  10  may be further programmed to output particular additional data or pins  18  and  20  during the diagnostic mode, which data may be sent to a computer for analysis through pins  35  and  40  and ports  4  and  5  of connector  30 . For example, microcontroller  10  may be programmed to monitor the operation thereof and output a signal or signal on pins  38  and/or  40  when a particular condition, such as a particular current or voltage level, is detected. Alternatively, microcontroller  10  may be programmed to use pins  18  and  20  instead of pins  22  and  24  to output the data and clock signal described above, in which case ports  4  and  5  would be connected to digital-to-analog converter  50  instead of ports  6  and  7 .  
         [0021]     Thus, the present invention enables a single connector to be used for both the programming of a microcontroller and the subsequent evaluation of the programming (diagnostic mode). As a result, the efficiency of software development for microcontrollers is improved while at the same time reducing the cost associated therewith.  
         [0022]     While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.