WO1991007753A1

WO1991007753A1 - In-circuit programming of integrated circuits

Info

Publication number: WO1991007753A1
Application number: PCT/AU1990/000538
Authority: WO
Inventors: Lawrence James Millett
Original assignee: Signalling Technology Pty. Ltd.
Priority date: 1989-11-08
Filing date: 1990-11-08
Publication date: 1991-05-30

Abstract

A programming wand (10) for programming in-circuit integrated circuits is described. The programming wand (10) comprises a head (13) having a plurality of electrical contacts (22-25), to which is connected a cable (11) which is terminated by a connector (12) at a programming means in the form of a personal computer (16). Programming of an integrated chip (21) mounted in a circuit board (20) is effected by contacting the head (13) with the integrated circuit (21) such that contacts (22-25) within the head (13) form an electrical connection with programming pins (26-29) on the integrated circuit (21). The integrated circuit (21) is received in part in the recess (17). The programming signals are then transferred from the personal computer (16) via the connector (12) and the cable (11). In another embodiment, the integrated circuit (21) serves as a temporary store for programming data and passes the data to another integrated circuit (30) on the interconnecting signal lines (31-33) to effect programming of that other integrated circuit (30). The integrated circuit (30) can be such as a non-volatile memory.

Description

IN-CIRCUIT PROGRAMMING OF INTEGRATED CIRCUITS

Technical Field

This invention relates to the programming of in-circuit integrated circuits.

In this specification, the apprevlation, IC, will be used interchangably with the expression, Integrated Circuit.

Background of the Invention

One very common type of integrated circuit is the memory, which often will be provided as stand-alone, but also can form part of a larger integrated circuit such as a microprocessor.

The majority of application-specific memory information such as programs, operating systems, fixed data or user specific information is stored in non-volatile memories, such as ROMs, which are programmed after manufacture.

In some instances it is necessary that programming be performed when a memory is in-circuit. That is, the memory is connected as a part of a larger circuit. In-circuit programming is known to be achieved by the provision of suitable contacts on the circuit board in which the memory is mounted, perhaps as a connector, free-standing pins or solder pads. These connectors connect in turn to the programming or input data pins on the memory. A disadvantage of this technique is that excessive surface area is used or otherwise wasted, which has substantial consequences where the minimization of the area occupied by componentry is an important design criteria. Another known method for achieving the programming (or reprogramming) of ICs is to perform the programming remote from the circuit board. That is, the IC must be removed from the circuit board. Usually ICs are installed on a circuit board by soldering their pins to the circuit board, requiring unsoldering to effect programming, which may be impracticable or cause irrepairable internal damage.

An alternative is to provide a socket soldered onto the circuit board, thereby enabling the continued removal of an IC from the socket. One disadvantage with this technique is that extra surface area is occupied by the socket, and is therefore effectively wasted. Such sockets increase the height or clearance requirement of the board, and this too has size implications for the finished product containing the circuit board. Also, the pins of the IC can be broken through continued removal from or insertion into the socket.

The present invention provides for ease of programming of in-circuit integrated circuits alleviating the need to remove the integrated circuits, and avoiding wastage of circuit board area.

Disclosure of the Invention

Therefore, the invention provides a method for programming in-circuit integrated circuits, comprising the steps of:

(a) contacting a programming wand with the integrated circuit, the programming wand having a head with a plurality of electrical contacts in the same orientation as programming pins on the integrated circuit and a cable connected both to the head and to a terminating connector, the said connector also being adapted to connect to a programming means, wherein the contacting forms an electrical connection between the programming pins and the contacts; and

(b) effecting programming by passing signals from the programming means via the programming wand to the programming pins on the integrated circuit. The invention also provides a method for programming in-circuit integrated circuits, comprising the steps of:

(a) contacting a programming wand with a first integrated circuit, the programming wand having a head with a plurality of electrical contacts in the same ^~" orientation as programming pins on the first integrated circuit and a cable connected both to the head and to a terminating connector, the said connector also being adapted to connect to a programming means, wherein the contacting forms an electrical connection between the programming pins and the contacts;

(b) passing programming signals to be temporarily stored in a memory of the first integrated circuit from the programming means via the programming ^' wand and the programming pins; and

(c) effecting programming of a second integrated circuit in communication with the first integrated circuit by passing the temporarily stored signals to the second integrated circuit.

The invention further provides a programming wand for programming ln-circult integrated circuits, comprising: a head having a plurality of electrical contacts in the same orientation as programming pins on an integrated circuit; a cable connected at one end to the contacts of the head; and a terminating connector connected to the other end of the cable, the connector being adapted for connection to a programming means; whereby, programming of the integrated circuit is achieved by contacting the contacts with the pins and passing signals from the programming means to the integrated circuit. Brief Description of the Drawings

In order that the invention can be more fully explained, particular embodiments will be described with reference to the accompanying drawings, in which: Figure 1 shows a general configuration of a system incorporating a programming wand constructed in accordance with the invention;

Figure 2 shows a circuit board containing an integrated circuit to be programmed, and detail of the programming wand of Figure 1;

Figure 3 shows interconnection details between the programming wand, a microprocessor IC and an EEPROM;

Figure 4 shows an alternative configuration of a programming wand; and Figure 5 shows detail of the programming interface wiring configuration.

Description of Preferred Embodiments

The embodiments to be described refer firstly to direct programming of a microprocessor containing a memory (Figure 2), but could equally apply to the direct programming of a stand-alone memory. Secondly, a method of referred programming of a stand-alone non-volatile memory such as an EEPROM will be discussed, in which data is temporarily stored in the memory of a microprocessor, then manipulated to provide correct timing to program that EEPROM. An example of such will be discussed with reference to Figure 4.

The system shown in Figure 1 relates to the first embodiment, and includes a programming wand 10 comprised essentially of a programming head 13, a connecting cable 11 and a terminating connector 12. Also shown is an in-line connector 15, the purpose of which will be described later. The wand 10 is connected to a programming means, in this example being a personal computer 16. The programming means could equally be any other suitable device having a programming and I/O capability. The connector 12 connects with the personal computer 16 through a D-type connector 18.

The connector 12 is further described in Figure 5, and in the present embodiment is merely a passive buffer, since output signals from the personal computer 16 are compatible with the physical logic levels required for the microprocessor to be programmed. If this were not the case, the interface would contain the necessary electronics for converting the output signals from the personal computer 16 to the physical logic levels required by the specific integrated circuit implementation. The personal computer 16 provides the environment for a programmer/operator to view the contents of a memory and/or effect programming of the memory via execution of a suitable program. The program itself will provide for translation of a higher level function to machine code which, as discussed, is then converted to physical logic levels by the connector 12. The actual detail of the transfer will be described presently.

Figure 2 shows further detail of the programming wand 10 in relation to a printed circuit board 20 and a microprocessor IC 21 mounted thereon. Also shown is an EEPROM 30. In reality, a large number of other components would be packed onto the circuit board 20, however, the present simplified arrangment has been chosen to illustrate the principles of the invention more clearly. In the final configuration, there would be no unused surface area on the circuit board.

The head 13, is formed to have a recess 17 of complementary shape to the external packaging of the IC 21, only being slightly larger, such that the head 13 can fit over a portion of the IC 21 for the purpose of implementing programming.

The head 13 contains electrical contacts 22-25, which in this embodiment are within the recess 17, as can be clearly seen in the cut-away view of Figure 2. The contacts have the same general shape as the pins on the IC 21. Each contact is soldered or otherwise fixed to one respective conductor within the cable 11. It is usual to provide only the necessary electrical contacts for connection with the actual programming pins on the IC 21, although an earth pin and power supply are most often provided to power the IC 21. The power supply, if provided, would allow programming to take place even if there is no power supplied to the circuit board 20, ie., the circuit board could effectively be switched-off and programming still take place.

Figure 3 shows the I/O pin configuration and interconnection for the microprocessor IC 21, (and the EEPROM 30) to the programming head 13.

The microprocessor IC 21 in this example is a proprietary design, however, other microprocessors have similar pin/signal configurations, hence could be programmed in the same manner. The programming pins 26-29 are configured to be:

RESET - reset SERI - serial input to microprocessor, which is connected to the memory space (RAM 34) SERC - serial clock

SERO - serial output, which is connected to the memory space (RAM 34)

Figure 5 shows the wiring configuration of the connector 12, which completes the signal paths between the personal computer 16 and the microprocessor 21. The programming procedure is initiated by an opperator positioning the head 13 over the IC 21 such that the electrical contacts 22-25 contact the programming pins 26-29. Once the connection has been made, the operator of the system can proceed in any one of the following four modes: (a) Run program immediately

(b) Read contents of microprocessor running

(c) Modify contents of microprocessor running

(d) Program EEPROM from microprocessor running

The option (c) is directly relevant to the first embodiment.

The host software running on the personal computer 16 arranges the reading or writing of data from the printer port (at connector 18) by a direct memory accessing technique utilising the basic machine code instructions "OUT" and "INP". The software directly addressed the printer port using these instructions, with the port number being contained in the bios ROM.

Taking the mode (c) option, it is desired to program (modify contents) of the RAM 34 within the microprocessor 21 as shown in Figure 3.

Therefore, to effect programming of the RAM 34, the following steps are performed -

(1) Reset microprocessor with SERI high. (2) Enter modify mode (c) by clocking in 2 bit command.

(3) Transfer 256 bits of data using SERC and SERI.

(4) Reset microprocessor with SERI high. (5) Clock 256 bits of data out of the microprocessor using SERC and SERO. (6) Verify this with original data to confirm correct transfer.

The data has now been programmed to the RAM 34, and remains to effect operation of the microprocessor IC 21 until such time as the power supply to the IC is removed. In order that the orientation of the programming wand 10 is correct with respect to the IC 21, an index mark 14 is placed on the programming wand to coincide with an identifying mark 40.

The programming wand 10 may also be physically polarised if the IC 21 is similarly polarised.

As foreshadowed, a second embodiment is to use the RAM 34 of the microprocessor 21 as a temporary storage for subsequent programming^* of a stand-alone memory, such as the EEPROM 30. This is mode (d) discussed above.

One reason for using such an indirect programming, is that for certain memory ICs the timing of data transfer must be specifically controlled. The microprocessor 21 can provide the necessary timing, although the programming wand 10 could be used directly, requiring careful timing implementation from the personal computer. That is, it is easier to use the precise timing regime already provided by the microprocessor, thereby avoiding unnecessary duplication of effort.-

The EEPROM 30 is connected to the microprocessor 21 by lines 31-33 on the circuit board 20 as shown in Figures 2 and 3. The output signal lines from the microprocessor 21 are:

EPCS - EEPROM chip select EPCK - EEPROM chip clock

EPIO - EEPROM input/output

Programming of the EEPROM 30 is performed once all the data is received in the RAM 34 of the microprocessor 21, so the process can be considered essentially as a continuous operation.

The EEPROM has complimentary signal lines which are -

CS - Chip Select SK - Serial Clock

DI/DO - Data Input/Output

The microprocessor 21 once having received the data receiving from the personal computer 16 then signals the personal computer that it should not be sent further data (SERO line set HIGH), then frames the data m RAM 34 into a timing window in accordance with the specifications of the EEPROM, having already chip selected the EEPROM on EPCS, then serially loads the data to the EEPROM from EPIO. Once all the data has been written to the EEPROM, it is then read back to the RAM 34 and back again to the software running in the personal computer 16 to be verified. The complete sequence, including the steps discussed above, is as follows:

(1) Reset microprocessor with SERI high.

(2) Enter modify mode (c) by clocking in 2 bit command.

(3) Transfer 256 bits of data using SERC and SERI. < ⁴ ■* Reset microprocessor with SERI high.

(5) Enter EEPROM program mode (d).

(6) Reset microprocessor with SERI low to enter normal operating mode (stand alone). This reads the EEPROM into the microprocessor memory and runs the program based on this information.

(7) Reset the microprocessor again (which does not change the internal meaning provide power is not removed with SERI high). (8) Enter the read mode (b).

(9) Clock 256 bits of data out of the microprocessor using SERC and SERO.

(10) Verify this with original data to confirm correct transfer. Once the data is transferred to the EEPROM, it will be retained, and every time the microprocessor is powered up, will be written back to the RAM 34 for use in execution of the function achieved by the whole circuit of the circuit board 20.

In the present example, the programming wand 10 contacts the pins of IC 21 from the component side of printed circuit board 20. It would be equally convenient to have the programming wand 10 adapted to contact the pins of IC 21 from the solder side of the printed circuit board 20. In order to achieve this alternative function, the head 13 would require a different configuration, such that the electrical contacts 22-25 were extended from the head 13. Further, it may be preferable to provide the electrical contacts of the programming wand 10 with a concave extremity such that they can receive the pointed ends of the programming pins of the integrated circuit for correct and reliable electrical contact.

Briefly considering Figure 5 in more detail, the 5V supply required for the output line, the pull-up resistors and the emitter follower transistor configuration can be provided by an external or internal regulated power supply which can receive its supply by any suitable connection. The signal lines to the head 13 have been described previously, and the signal lines back to the personal computer 16 are typically those of a parallel printer port having a centronic interface, using data bits DO, Dl, D2, D7, and the Busy input line. The PE lines is the printer enable, which is connected to the D7 line by the emitter follower configuration, which has the function of allowing the programming software to determine that the programming interface is connected to the personal computer 16, and to know that power is applied, achieved by a high-low transition on D7, which should be returned in sympathy to the personal computer on PE.

Returning to Figure 4, it was previously discussed that the programming head 13 could be directly contacted with the programming pins (CS, SK, DI/DO) to directly programme the EEPROM 30.

For this purpose the head 13 must be of a suitable shape to receive the EEPROM 30 within the recess

17, and the provision of the in-line connector 15 (Figure

1) makes substitution of the correct head 13 possible.

The head 13 would be wired to be compatible with a standard cable configuration, and in this example, has only three electrical contacts 43-45.

The head 13 again has an index 14 for correct alignment with the EEPROM identifying mark 41.

From the foregoing it can be seen that the invention provides method and apparatus that permit the programming of in-circuit integrated circuits, with the advantage, at least, that circuit board surface area is not wasted.

The embodiments described can easily be fabricated by standard manufacturing techniques, and has industrial application in any circumstance where user specified programs or data is required to be changed regularly, such as in secured communication systems.

Claims

CLAIMS :

1. A method for programming in-circuit integrated circuits, comprising the steps of:

(b) effecting programming by passing signals from the programming means via the programming wand to the programming pins on the integrated circuit.

2. A method as claimed in claim 1, including the further step prior to step (b) of converting the signals to physical logic levels suitable for accomplishing programming of the integrated circuit.

3. A method for programming in-circuit integrated circuits incorporating a memory, comprising the steps of:

<b) effecting programming of the memory by passing signals from the programming means via the programming wand to the programming pins of the integrated circuit.

4. A method as claimed in claim 3, including the further step prior to step (b) of converting the signals to physical logic levels suitable for accomplishing programming of the memory.

5. A method for programming in-circuit integrated circuits, comprising the steps of:

(a) contacting a programming wand with a first integrated circuit, the programming wand having a head with a plurality of electrical contacts in the same orientation as programming pins on the first integrated circuit and a cable connected both to the head and to a terminating connector, the said connector also being adapted to connect to a programming means, wherein the contacting forms an electrical connection between the programming pins and the contacts,-

(b) passing programming signals to be temporarily stored in a memory of the first integrated circuit from the programming means via the programming wand and the programming pins; and

6. A method as claimed in claim 5, wherein the step of effecting programming includes the further step prior to step (b) of the first integrated circuit manipulating the temporarily stored signals to provide correct timing for the passing of the signals to the second integrated circuit.

7. A method as claimed in either one of claims 5 or 6, wherein the first integrated circuit is a microprocessor and the second integrated circuit is a non-volatile memory.

8. A programming wand for programming in-circuit integrated circuits, comprising: a head having a plurality of electrical contacts in the same orientation as programming pins on an integrated circuit; a cable connected at one end to the contacts of the head; and a^' terminating connector connected to the other end of the cable, the connector being adapted for connection to a programming means; whereby, programming of the integrated circuit is achieved by contacting the contacts with the pins and passing signals from the programming means to the integrated circuit.

9. A programming wand as claimed in claim 8, wherein the head is provided with a recess of slightly larger complementary shape than the integrated circuit, being adapted to receive a portion of the integrated circuit within the recess, and within which the electrical con-tacts are positioned so that with the head placed over the integrated circuit the electrical contacts are correctly oriented with the programming pins.

10. Apparatus as claimed in either of claims 8 or 9, wherein the electrical contacts are substantially of the same shape as the programming pins.

11. Apparatus as claimed in either of. claims 8 or 9, wherein the electrical contacts have a concave extremity so that the ends of the programming pins can in part be received in complementary pointed extremities of the programming pins.

12. Apparatus as claimed in any one of claims 8 to

11, wherein the terminating connector includes circuitry to convert data from the programming means to physical logi-c levels suitable for accomplishing programming of the integrated circuit.

13. Apparatus as claimed in any one of claims 8 to

12, wherein the cable has an in-line connector to allow interchange of the head to suit the integrated circuit to be programmed.

14. A method as claimed in any one of claims 1 to 7, and as herein described with reference to any one of the examples shown in the accompanying drawings.

15. A programming wand as claimed in any one of claims 8 to 13, and as herein described with reference to any one of the examples shown in the accompanying drawings.