JP2003167753A - Electronic equipment and check system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment that can download and execute a program stored in an external memory without influencing an internal bus via simple communication processing. <P>SOLUTION: A laser printer 1 has a serial memory 12 storing a function extending program not connected to the internal bus connecting a CPU 51, a ROM 52, a RAM 53 and an ASIC 54, but connected to a serial communication port of the ASIC 54 via a serial communication line L1. The presence of the serial memory 12 does not adversely influence data transmission in the internal bus to pose a problem. The connection of the serial memory 12 and the ASIC 54 by the serial communication line L1 with fewer signal conductors can suppress superimposed noise on the signal conductors. A normal operation can be ensured in a main program stored in the ROM 52. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device and an inspection system capable of appropriately downloading and executing a program stored in an external memory.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
In a process of manufacturing an electronic device, a CPU, R mounted on the printed circuit board (hereinafter simply referred to as “substrate”) having the specific function is mounted on the substrate before being incorporated in the electronic device.
A function check is performed to check whether or not a controller including an OM, a RAM, or an ASIC (semiconductor integrated circuit for a specific application) normally functions, and only a substrate that passes the function check is incorporated in an electronic device. .

In this function check,
Specifically, as shown in the schematic view of FIG. 7, for example, in the main control board 161, the controller 10
5, CPU 152, ROM 152, RAM 15
3. Pins (needle ridges) P0 for external signal line connection are installed at predetermined points of the plurality of internal buses B that connect the ASIC 154 and the like to each other. Then, for this pin P0, a function check program (hereinafter referred to as "F / C
Flash ROM 11 storing "program")
Connect the ends of the parallel communication lines L extending from 2 (in the figure, for simplicity, the "parallel communication line L" and the "plurality of internal buses B" are each represented by one line. ing).

In this state, the CPU 151 causes the RO
This F / C is based on the program stored in M152.
Program from flash ROM 112 to RAM 153
Download and run. In this case, a method of pre-installing the F / C program in the ROM 152 may be considered. However, the capacity of the F / C program is relatively large, and if the F / C program is installed in the ROM 152 in the form of a mask ROM, the program is later written. The contents of can not be rewritten. Therefore, in general, the main control board 16
The F / C program is downloaded from a flash ROM 112, which is an external memory mounted on a substrate 111 independent of the CPU 1.

Then, the inspection result obtained by executing the F / C program at this time is the ASIC 154 and the communication line L0.
Also, it is transmitted to the data transmitting / receiving device PC such as an external personal computer via the I / O interface 155. The inspector confirms the inspection result displayed on the display of the data transmitting / receiving device PC, and conveys only the main control board 161 that has passed this inspection to the assembly process into the electronic device.

However, the flash ROM 11 for the internal bus B is thus checked at the time of function check.
When 2 is connected, the load on the data transmission of the internal bus B increases. On the other hand, when this function check is completed, the flash ROM 112 is removed and the load is removed. For this reason, the signal waveform of the transmission data may differ between the function check and the actual execution of the main program. Also, flash ROM1
There is a case where noise is superimposed on the parallel communication line L separately drawn from 12 to disturb the signal waveform. As a result, RO
There is a problem that the main program stored in M152 may not operate normally.

Further, such a problem is not limited to the case where the F / C program is executed. For example, a function expansion program for adding the function of the main program stored in the ROM of the main body is read from the external flash ROM. It also occurred when reading. The present invention has been made in view of such a problem, and provides an electronic device and an inspection system capable of downloading and executing a program stored in an external memory by a simple communication process without affecting the internal bus. The purpose is to do.

[0008]

According to another aspect of the present invention, there is provided an electronic apparatus comprising: a CPU for executing arithmetic processing according to a predetermined control program; a ROM for storing the control program; To temporarily store
A controller is provided in which M and a semiconductor integrated circuit having a logic circuit unit for executing a predetermined process are connected to each other via an internal bus. Then, the control signal output from the CPU is output to at least one of the plurality of control targets via the logic circuit section to perform a predetermined operation. The “semiconductor integrated circuit” mentioned here includes an ASIC having a so-called user logic section as the “logic circuit section”.

The semiconductor integrated circuit has a serial communication port for receiving, by serial communication, a function expanding program stored in a rewritable external memory having a serial communication function. Then, the CPU detects the function expanding program from the external memory via the semiconductor integrated circuit in accordance with the control program, reads the function expanding program when the function expanding program is detected, and reads the R program.
Store in AM. Then, the function of the control program is expanded using the function expanding program stored in the RAM. The "external memory" referred to here is not limited to the serial memory as long as it has the serial communication function as described above, and includes a parallel memory having the serial communication function.

According to this structure, the external memory is not connected to the internal bus but is connected to the serial communication port of the semiconductor integrated circuit via the serial communication line.
Therefore, the presence of the external memory does not impose a heavy load on the internal bus for data transmission, and does not affect the waveform of the signal flowing through the internal bus. Further, since the external memory and the semiconductor integrated circuit are connected by the serial communication line having a small number of signal lines, it is possible to suppress the superimposed noise via the communication line. Even if noise is superimposed, since it is not directly connected to the internal bus, it does not disturb the waveform of the signal flowing through the internal bus. As a result, communication between the CPU, RAM, ROM, and semiconductor integrated circuit can be maintained normally, and normal operation of the main program stored in ROM can be ensured.

Further, since the port on the semiconductor integrated circuit side used in this function expansion processing is a serial communication port and a serial communication line is connected to this port, the number of signal lines is small and the layout thereof is small. Can be simplified, which is convenient for wiring. Also, since the number of ports used on the semiconductor integrated circuit side can be minimized,
Other ports of the semiconductor integrated circuit can be effectively utilized for other important applications other than the function expansion application.

Further, since the external memory is rewritable, it is not necessary to disassemble the electronic device and replace it with another memory when the function expansion program is improved or modified, and the external communication process is performed. Since the contents of the function expansion program can be rewritten as appropriate, it can be provided for the convenience of the user.

Further, the technical idea can be applied not only when downloading the function expanding program but also when downloading and executing the F / C program at the time of the function check described above. That is, also in the electronic device according to the second aspect, similarly, a CPU that executes arithmetic processing according to a predetermined control program, a ROM that stores this control program, a RAM that temporarily stores data, and a predetermined A semiconductor integrated circuit having a logic circuit unit for executing processing is connected to each other via an internal bus. And CPU
The control signal output by the device is output to at least one of the plurality of control targets via the logic circuit unit to perform a predetermined operation.

The above semiconductor integrated circuit has a serial communication port for receiving by serial communication the inspection program stored in a rewritable external memory having a serial communication function. Then, the CPU receives the inspection program (F / C program) from the external memory according to the control program, stores the inspection program in the RAM, executes the inspection program stored in the RAM, and inspects the controller. Perform processing. The “external memory” here is not limited to a serial memory, but includes a parallel memory having a serial communication function.

In such a configuration, since the inspection program itself is one independent program, when it is downloaded into the RAM, it is functionally separated from the main program stored in the ROM of the main body and executed. It will be. According to this configuration, the inspection program can be downloaded by serial communication between the semiconductor integrated circuit and the external memory, as in the case of claim 1.
Further, even if the external memory is removed after the inspection process is completed, the waveform of the signal flowing through the internal bus is not changed. Therefore, the presence of this external memory does not affect the internal bus, and the same effect as in the case of claim 1 can be obtained.

In this case, for example, as described in claim 3, the external memory is mounted on a board independent of the main control board to form a part of the external memory unit, and the electronic device is connected to the external memory unit. It is preferable to have a slot for detachably connecting to the outside.

According to this structure, the external memory unit can be easily attached to and detached from the electronic device through the slot, which is convenient for handling. Moreover, if the configuration is such that the function expanding program and the inspection program can be selectively downloaded as in the electronic device according to the fourth aspect, versatility is enhanced.

That is, the electronic device according to claim 4 also
CP that executes arithmetic processing according to a predetermined control program
A controller in which a U, a ROM storing this control program, a RAM temporarily storing data, and a semiconductor integrated circuit having a logic circuit unit for executing a predetermined process are connected to each other via an internal bus. Equipped with. Then, the control signal output from the CPU is output to at least one of the plurality of control targets via the logic circuit unit to execute a predetermined operation.

The above semiconductor integrated circuit has a serial communication function, and is a rewritable first storage function storing program.
Each of the memories and a rewritable second memory having a serial communication function and storing an inspection program is provided with a serial communication port for serial communication. Further, the semiconductor integrated circuit communicates with the first memory and stores a function expansion program in the RAM in a normal mode,
A mode setting unit is provided for selectively setting in advance one of the inspection modes capable of storing the inspection program in the RAM by communicating with the second memory.

Then, when the normal mode is set by the mode setting means, the CPU detects the function expansion program in one memory through the semiconductor integrated circuit according to the control program, and expands the function. When the program for use is detected, it is read and stored in the RAM. Then, the function expansion program stored in the RAM is used to expand the function of the control program, and the processing based on the expanded function is performed.

On the other hand, when the inspection mode is set by the mode setting means, the CPU receives the inspection program in the second memory via the semiconductor integrated circuit according to the control program and stores it in the RAM. And this R
The inspection program stored in the AM is executed to inspect the controller.

The "mode setting means" here may be a hardware switch such as a DIP switch which is manually switched, or the state of a specific port of the semiconductor integrated circuit is set to "High" by communication from the outside. Or a soft switch for switching to "Low".

According to such a configuration, the first memory or the second memory can be selectively accessed by the setting by the mode setting means, and the function expansion program or the inspection program can be arbitrarily downloaded.
Further, since the port on the semiconductor integrated circuit side used at that time is a specific serial communication port, the number of ports used on the semiconductor integrated circuit side is not increased.

Therefore, it is possible to obtain the same effects as those of the electronic apparatus according to the first and second aspects and to enhance the versatility thereof. Further, the timing of the mode check whether it is the “normal mode” or the “inspection mode” can be arbitrarily set on the main program stored in the ROM. To
The CPU may detect whether the setting mode by the mode setting means is the normal mode or the inspection mode when the controller is activated by turning on the power.

With this configuration, the function expansion process or the inspection process can be completed before the main process in the main program is executed, and the main program can be executed smoothly. Further, even when there are two kinds of download memories, at least one of the first memory and the second memory is mounted on a board independent of the main program as described in claim 6. It is convenient in terms of handling that the electronic device is provided with a slot for detachably connecting the external memory unit from the outside, which constitutes a part of the external memory unit.

By the way, since the first memory stores the function expansion program, it is preferable that the first memory is incorporated in the electronic equipment in preparation for the version upgrade of the program. On the other hand, the second memory stores an inspection program, but this inspection program is generally executed before the main control board is incorporated into an electronic device, and is executed after the main control board is attached. Since it is rare, the need to mount it on the main control board is relatively small.

Therefore, as described in claim 7, the first memory is mounted on the main control board including the controller, and the first memory and the semiconductor integrated circuit connect the wiring on the main control board. It may be serially connected via.

As a specific mode for connecting both the first memory and the second memory to the serial communication port of the semiconductor integrated circuit, for example, the one described in claim 8 can be considered. That is, in the electronic device according to claim 8, the first memory is connected to the data line extending from the serial communication port on the main control board,
It is configured to be connectable or non-connectable to the select line extending from this serial communication port. The "data line" here means one of the lines forming the serial communication line, and means a communication line for transmitting the data stored in the memory to the semiconductor integrated circuit. on the other hand,
The “select line” means a communication line for transmitting a select signal output to the memory when the semiconductor integrated circuit side acquires the data stored in the memory. Therefore, the semiconductor integrated circuit side can acquire the stored data through the data line from the memory that outputs the select signal through the select line.

When the first memory is not connected to the select line, the second memory is in contact with both the select line and the data line so that the second memory can be connected or disconnected. That is, when the first memory is not connected to the select line, the function expanding program stored in the first memory is not output to the semiconductor integrated circuit side. Therefore, when the second memory is in contact with and connected to both the select line and the data line, the select signal output from the semiconductor integrated circuit side is input to the second memory, and the second memory outputs the select signal via the data line. The inspection program is output. Therefore, the semiconductor integrated circuit side can selectively acquire the inspection program.

On the other hand, when the first memory is connected to the select line, the second memory is removed (or originally not connected). Therefore, the select signal output from the semiconductor integrated circuit side is input to the first memory, and the function expansion program is output from the first memory via the data line. Therefore, the semiconductor integrated circuit side can selectively acquire the function expansion program.

For switching the connection or non-connection state of the first memory to the select line, a manually operated hardware changeover switch may be used. A method is conceivable in which the disconnection portions are connected to each other by connecting the disconnection portions by mounting a specific element in the connected state.

As a more specific configuration, as will be described in the embodiments to be described later, for example, a part of the select line is initially disconnected so that the semiconductor integrated circuit and the first memory are not connected and the select line is also connected. And needle points are provided at specific points on the data line. The inspection program can be downloaded by bringing the signal lines (select line and data line) extending from the second memory into contact with the needles only during the inspection mode. Then, when the inspection mode ends, the second memory is removed, a resistor or the like is mounted on the disconnection portion of the select line to bring the semiconductor integrated circuit and the first memory into a connected state, and the function expansion program for the first memory is executed. It can be configured to be downloadable.

Further, by adopting such a mode that the signal lines on the second memory side are brought into contact with each other, the second memory can be easily removed after the inspection process is completed. Further, as described in claim 9, it is preferable that each of the memories is a serial flash ROM. Flash ROM
Is the largest of the rewritable ROMs in general,
This is because the function expansion program or the inspection program can be stored with a sufficient margin.

In some cases, the above inspection program is used only when checking the controller on the main control board and does not need to be resident in the electronic device. In this case, the technical idea of the present invention can be constructed as a board-level inspection system.

That is, an inspection system according to a tenth aspect of the present invention includes a CPU for executing arithmetic processing according to a predetermined control program, a ROM for storing the control program,
An inspection process is performed on a controller in which a RAM for temporarily storing data and a semiconductor integrated circuit having a logic circuit unit for executing a predetermined process are connected to each other via an internal bus.

The semiconductor integrated circuit has a serial communication port for receiving the inspection program stored in the rewritable external memory having the serial communication function by serial communication. Then, according to the control program, the CPU receives the inspection program from the external memory, stores it in the RAM, executes the inspection program stored in the RAM, and performs the inspection processing of the controller.

According to this structure, the same effect as the electronic device according to the second aspect can be obtained.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] In this embodiment, the present invention is embodied in a laser printer as an electronic device, and FIG. 1 is a block diagram showing the main configuration of the laser printer.

As shown in the figure, the laser printer 1 is
Panel unit 2 for the user to set various modes in advance,
An engine unit 3 including drive circuits for various mechanisms incorporated therein, various sensors, and the like, a scanner unit 4 that performs exposure during printing, and a predetermined communication with these panel unit 2, engine unit 3, and scanner unit 4 The controller 5 and the like that execute print control processing are provided.

The controller 5 outputs a control signal to various mechanisms in the laser printer 1 based on a predetermined control program, a ROM 52 in which various control programs are stored, an external device such as a personal computer or a host computer. RAM 53 provided with various memories such as a reception buffer for storing print data received from the data transmission / reception device PC, and a user logic section 54a (logic circuit section) in which a logic circuit is arbitrarily programmed according to a specific application. An ASIC 54 and an I / O interface 55 for connecting a communication cable with the data transmitting / receiving device PC are provided. These are mounted on the main control board 61 and are connected via an internal bus.

On the other hand, the engine section 3 is a main motor drive circuit for driving a main motor for operating a paper feed roller, a resist roller, a photosensitive drum, a heating roller, a pressure roller, a paper discharge roller, a pinch roller, etc., which are not shown. ,
Various circuits such as an electric field generation circuit for generating a high-voltage electric field on the photosensitive drum, the transfer roller, the charger, the developing roller and the cleaning roller, a fixing heater driving circuit for operating the fixing heater in the heating roller, and toner Toner sensor that detects the remaining amount, paper feed sensor that detects the paper feed status,
Various sensors such as a paper discharge sensor for detecting the paper discharge state are provided.

Then, the CPU 51 performs necessary communication processing with the panel unit 2 and the scanner unit 4 via a predetermined communication line, while accessing the engine unit 3 via the ASIC 54 and a predetermined communication line to access various circuits. Of the predetermined control signal and the reception of output signals from various sensors.

Further, on the lower front surface of the laser printer 1,
A slot 6 for detachably mounting the external memory unit 10 is provided. This external memory unit 1
0 is configured by mounting a serial memory 12 (external memory) on a printed circuit board 11 independent of the main control board 61. The serial memory 12 is composed of a flash ROM having a serial communication function, and a function expanding program for expanding the function of the main program stored in the ROM 52 is stored therein.
Then, the serial communication line L1 extending from a specific serial communication port of the ASIC 54 is connected to the serial memory 12, and the CPU 51 is configured so that the function expansion program can be read from the serial memory 12 via the ASIC 54. There is.

More specifically, the ASIC 54 is provided with a changeover switch 54b (mode setting means) for presetting whether or not to access the serial memory 12.
In this embodiment, the changeover switch 54b is a dip switch exposed to the outside of the laser printer 1 so that the user can manually switch the switch to "High" or "Low" from the outside. .

Then, the changeover switch 54b is set to "Lo
When the power is turned on and the controller is activated in the state set to "w", the CPU 51 accesses the serial memory 12 according to the main program stored in the ROM 52, and shifts to the function expansion mode in which the function expansion program can be read. .

On the other hand, the changeover switch 54b is "High".
When the power is turned on and the controller is activated in the state set to, the CPU 51 executes the main program stored in the ROM 52 without accessing the serial memory 12. As described above, in the laser printer 1 according to the present embodiment, the serial memory 12 includes the CPU 51 and the ROM.
52, the RAM 53, the ASIC 54 and the like are not connected to the internal bus, but are connected to the serial communication port of the ASIC 54 via the serial communication line L1. Therefore, there is no problem that the presence of the serial memory 12 imposes a load on the internal bus and adversely affects the data transmission.

In addition, the serial memory 12 and the ASIC 54
Since and are connected by the serial communication line L1 having a small number of signal lines, it is possible to suppress the superimposed noise on the signal lines. As a result, CPU51, ROM5
The communication between the RAM 2, the RAM 53, and the ASIC 54 can be normally maintained, and the normal operation of the main program stored in the ROM 52 can be ensured.

Further, since the serial communication line is connected to the serial communication port of the ASIC 54, the number of signal lines is small and the layout can be simplified, which is convenient for wiring. Further, since the number of ports on the ASIC 54 side used for storing the function expansion program can be minimized, other ports of the ASIC 54 can be effectively utilized for other important purposes.

Further, since the serial memory 12 is rewritable, if the function expanding program is improved or modified, its contents can be easily rewritten by communication from the data transmitting / receiving device PC, for example. , Can be provided for the convenience of the user. [Second Embodiment] This embodiment corresponds to a modification of the first embodiment and relates to an inspection system for performing a function check of a controller of a laser printer. Then, in the serial memory 212, the F /
It is also different from the first embodiment in that the C program is stored.

FIG. 2 is a block diagram of the inspection system according to this embodiment. However, regarding the main components,
Since it is the same as that shown in the embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.
In this embodiment, the CPU 51, the ROM 52, the RAM 53, and the AS mounted on the main control board 61.
Since the IC 54 is related to the inspection system that inspects whether the IC 54 normally functions, the configuration of the entire laser printer is not displayed.

The serial memory 212 is mounted on the printed board 11 independent of the main control board 61, and constitutes the external memory unit 210. And A
Pins P2 (needle ridges) for connecting an external signal line are provided at predetermined points of the serial communication line L2 extending from the serial communication port of the SIC 54 and formed as a pattern on the main control board 61. And
At the time of function check, the changeover switch 54b is set to "Low", and the power is turned on with the tip of the serial communication line extending from the serial memory 212 being in contact with the pin P2. Then, the CPU 51 recognizes that it is in the inspection mode, accesses the serial memory 212 in accordance with the main program stored in the ROM 52, reads the inspection program, and temporarily stores it in the RAM 53.
The inspection program is executed to perform the inspection process.

At this time, CPU 51, ROM 52, RA
Information indicating whether or not the M53 and the ASIC 54 are functioning normally is output to the data transmitting / receiving device PC via the I / O interface 55, and the inspector displays the information displayed on the display (not shown) of the data transmitting / receiving device PC. And check the function. And the main control board 61 that has passed this function check
Only built into the laser printer.

As described above, the AS
The inspection program is downloaded by serial communication between the IC 54 and the serial memory 212.
Further, even if the serial memory 212 is removed after the inspection process is completed, the waveform of the signal flowing through the internal bus is not changed. Therefore, this serial memory 212
The presence of the first bus does not affect the internal bus.
The same effect as that of the embodiment can be obtained. [Third Embodiment] This embodiment corresponds to a modification of the first and second embodiments, and has a configuration capable of selectively downloading the function expansion program and the inspection program. Different from both examples.

That is, as shown in FIG. 3, on the main control board 361, the first serial memory 312 (first memory) storing the function expanding program is mounted. The first serial memory 312 is composed of a rewritable flash ROM and is connected to the serial communication line L3 extending from the serial communication port of the ASIC 54. The serial communication line L3 includes a select line S1 and a data line D1 formed as a pattern on the main control board 361, and the ASIC 54 sends a select signal to the first serial memory 312 via the select line S1. , The first serial memory 3
The function extension program stored in 12 is connected to the data line D1.
It can be taken in via.

In this embodiment, this select line S
A disconnection portion is initially provided in a part of 1 as shown in the figure. By mounting a resistor R on this disconnection portion, a select signal flowing through the select line S1 can be transmitted to the first serial memory. Has become. Then, when the select signal is received on the side of the first serial memory 312, the data including the function expansion program is transferred to A via the data line D1.
It is transmitted to the SIC 54 side.

In addition, the select line S1 and the data line D
The first serial memory 322 storing the inspection program can be connected to the first terminal 1. That is, the second serial memory 322 is composed of a rewritable flash ROM and stores the inspection program. The second serial memory 322 is mounted on an external printed circuit board 321 independent of the main control board 361.
Two communication lines L4 for communicating with the SIC 54 are extended. The communication line L4 includes a select line S2 and a data line D2, and the tips of the lines can come into contact with pins (needle mountains) P3 provided at predetermined points on the select line S1 and the data line D1, respectively. ing.

The select line S is provided on the ASIC 54 side.
2 and the second serial memory 32 via the select line S2.
By transmitting the select signal to 2, the data including the inspection program stored in the second serial memory 322 can be taken in via the data line D2 and the data line D1.

The second serial memory 322 is connected to the select line S1 and the data line D1 for function check after the controller 305 is mounted on the main control board 361, but is removed when the function check is finished. Be done. For this reason,
As shown in FIG. 4, inside the laser printer 301,
Only the first serial memory 312 mounted on the main control board 361 is accommodated.

In this embodiment, the changeover switch 54b is set to "Lo
If it is "w", the mode is shifted to the inspection mode in which the function check is performed, and the changeover switch 54b is set to "Hig
If it is “h”, the function of the main program is expanded and executed, or the normal mode is executed in which the normal main program is executed as it is.

Next, a specific communication process in this embodiment will be described with reference to the flowchart of FIG. 5 and FIG. When the power of the controller on the main control board 361 is turned on, the CPU 51 first detects the setting state of the changeover switch 54b (S110), and determines whether or not the changeover switch 54b is "Low" (S1).
20).

When it is judged that the changeover switch 54b is set to "Low" (S120: YES),
Recognizing that the inspection mode is set, the select signal is output via the ASIC 54 (S130). At this time, since the select line S1 connecting the ASIC 54 and the first serial memory 312 is in a disconnection state as shown in FIG. 6A, the select signal is the select line S.
It is input to the second serial memory 322 side through 2 (dashed-dotted arrow), and the inspection program is output from the second serial memory 322 (solid arrow).

The CPU 51 executes the inspection program A
Stored in the RAM 53 via the SIC 54 (S140),
The inspection program stored in the RAM 53 is executed to perform the inspection process (S150). At this time, the CPU
51, ROM52, RAM53, and ASIC54,
The information on whether or not it is functioning normally is displayed in the I / O shown in FIG.
The data is output to the data transmission / reception device PC through the O interface 55, and the inspector confirms the information displayed on the display (not shown) of the data transmission / reception device PC to check the function. Then, only the substrate that has passed this function check is incorporated into the laser printer 301.

On the other hand, in S120, the changeover switch 5
When it is determined that 4b is not "Low" (that is, "High"), it is recognized as the normal mode, and the ASIC is recognized.
A select signal is output via 54 (S160). At this time, the disconnection portion of the select line S1 is shown in FIG.
Since the resistor R is mounted and connected and the communication line L4 connected to the second serial memory 322 is removed, the select signal is input to the first serial memory 312 side (one point). (Dashed arrow). Therefore, if the function expansion program is stored in the first serial memory 312, this is output (solid line arrow).

The CPU 51 uses the first serial memory 312
If it is determined that this function expansion program is output from (S170: YES), this function expansion program is stored in the RAM 53 via the ASIC 54 (S18).
0). Then, in the process of executing the main program stored in the ROM 52, the target processing is performed by appropriately using the function expansion program stored in the RAM 53 (S190).

On the other hand, in S170, the CPU 51
When it is determined that the function expansion program cannot be received from the first serial memory 312 (that is, there is no function expansion program) (S170: NO), the normal main program stored in the ROM 52 is executed (S20).
0).

As described above, in this embodiment, by mounting the resistor R and connecting / disconnecting the communication line L4, the first serial memory 312 or the second serial memory 322 can be selectively accessed. The function expansion program or the inspection program can be arbitrarily downloaded. Also, since the port on the ASIC 54 side used at that time is a specific serial communication port, the ASIC 5
It does not increase the number of ports used by No. 4.

Therefore, the same effects as those of the first and second embodiments can be obtained and the versatility can be improved. Although the embodiments of the present invention have been described above, it goes without saying that the embodiments of the present invention are not limited to the above embodiments and can take various forms within the technical scope of the present invention. Nor.

For example, in each of the above-described embodiments, an example in which the present invention is embodied in a laser printer or an inspection system for a controller of a laser printer is shown, but the invention can be similarly applied to electronic equipment other than the laser printer. Of course. In addition, in the first embodiment,
Although the example in which the function expansion program is stored in the serial memory 12 is shown, the inspection program may be stored in the serial memory 12 to perform the inspection process.

Further, in the third embodiment described above, the mode in which the disconnection portion of the select line S1 is connected by mounting the resistor R is shown. However, a hardware changeover switch is provided in the disconnection portion to select the selection line S1. The connection state may be changed appropriately.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a laser printer according to a first embodiment of the invention.

FIG. 2 is a block diagram showing an electrical configuration of an inspection system of a second embodiment.

FIG. 3 is a block diagram showing an electrical configuration of an inspection system of a third embodiment.

FIG. 4 is a block diagram showing an electrical configuration of a laser printer according to a third embodiment.

FIG. 5 is a flowchart showing a specific communication process according to the third embodiment.

FIG. 6 is an explanatory diagram showing a specific communication process according to the third example.

FIG. 7 is a block diagram showing an electrical configuration of a conventional inspection system.

[Explanation of symbols]

1, 301 ... Laser printer, 5 ... Controller, 6 ... Slot, 10, 210 ... External memory unit, 12, 212 ... Serial memory,
54 ... ASIC, 54a ... User logic part,
54b ... Changeover switch, 61, 361 ... Main control board, 312 ... First serial memory, 322 ... Second serial memory, S1, S2 ...
..Select lines, D1, D2 ... Data lines, R
··resistance

Claims (10)

[Claims] 1. A CPU that executes arithmetic processing according to a predetermined control program, and an RO that stores the control program.
A controller that connects M, a RAM for temporarily storing data, and a semiconductor integrated circuit having a logic circuit unit for executing a predetermined process to each other via an internal bus is provided. In an electronic device that outputs a signal to at least one of a plurality of control targets through the logic circuit unit and performs a predetermined operation, the semiconductor integrated circuit is stored in a rewritable external memory having a serial communication function. A serial communication port for receiving the program for expanding the function by serial communication, and the CPU executes the function from the external memory having the serial communication function via the semiconductor integrated circuit according to the control program. The extension program is detected, and when the function extension program is detected, it is read and stored in the RAM. Electronic apparatus, characterized in that to extend the functionality of the control program using the stored function expansion program. 2. A CPU that executes arithmetic processing according to a predetermined control program, and an RO that stores the control program.
A controller that connects M, a RAM for temporarily storing data, and a semiconductor integrated circuit having a logic circuit unit for executing a predetermined process to each other via an internal bus is provided. In an electronic device that outputs a signal to at least one of a plurality of control targets through the logic circuit unit and performs a predetermined operation, the semiconductor integrated circuit is stored in a rewritable external memory having a serial communication function. A serial communication port for receiving the checked inspection program by serial communication, the CPU receives the inspection program from the external memory according to the control program, and the RAM
The electronic device is characterized by executing the inspection program stored in the RAM and executing the inspection program stored in the RAM. 3. The external memory constitutes a part of the external memory unit, and has a slot for detachably connecting the external memory unit to the electronic device from the outside. The electronic device according to claim 1 or 2. 4. A CPU that executes arithmetic processing according to a predetermined control program, and an RO that stores the control program.
A controller that connects M, a RAM for temporarily storing data, and a semiconductor integrated circuit having a logic circuit unit for executing a predetermined process to each other via an internal bus is provided. In an electronic device that outputs a signal to at least one of a plurality of control targets via the logic circuit unit to execute a predetermined operation, the semiconductor integrated circuit has a serial communication function and stores a function expansion program. A rewritable first memory and a rewritable second memory having a serial communication function and storing an inspection program, a serial communication port for serial communication, and the function expansion by communicating with the first memory. A normal mode in which a test program can be stored in the RAM, and a test mode in which the test program can be stored in the RAM by communicating with the second memory. And a mode setting unit for selectively setting one of the check modes in advance, wherein the CPU, when the normal mode is set by the mode setting unit, according to the control program, The function expansion program is detected from the first memory via the semiconductor integrated circuit, and when the function expansion program is detected, the program is read and stored in the RAM, and the RA
When the function of the control program is expanded by using the function expanding program stored in M and processing based on the expanded function is performed, while the inspection mode is set by the mode setting unit, According to the control program, the inspection program is received from the second memory via the semiconductor integrated circuit and stored in the RAM, and the inspection program stored in the RAM is executed to execute the inspection process of the controller. The electronic device characterized by. 5. The CPU detects whether the mode set by the mode setting means is the normal mode or the inspection mode when the controller is activated by turning on the power. The electronic device according to 4. 6. A slot for at least one of the first memory and the second memory forming a part of an external memory unit, and a slot for detachably connecting the external memory unit to the electronic device from the outside. The electronic device according to claim 4, further comprising: 7. The first memory is mounted on a main control board including the controller, and the first memory and the semiconductor integrated circuit are serially connected via a wiring on the main control board. The electronic device according to claim 4 or 5, wherein 8. The first memory is connected to a data line extending from the serial communication port on the main control board, and is connected or not connected to a select line extending from the serial communication port. When the first memory is not connected to the select line, the second memory is in contact with both the select line and the data line and can be connected or disconnected. The electronic device according to claim 7, which has been performed. 9. Each of the memories is a serial flash R.
It is OM, The electronic device in any one of Claims 1-8 characterized by the above-mentioned. 10. A CPU that executes arithmetic processing according to a predetermined control program, and an R that stores the control program.
In an inspection system for performing an inspection process of a controller in which an OM, a RAM for temporarily storing data, and a semiconductor integrated circuit having a logic circuit unit for executing a predetermined process are connected to each other via an internal bus, The semiconductor integrated circuit includes a serial communication port for receiving, by serial communication, an inspection program stored in a rewritable external memory having a serial communication function, and the CPU is configured to operate in accordance with the control program. The RAM for receiving the inspection program from an external memory
And an inspection program stored in the RAM to execute an inspection program to perform an inspection process of the controller.