JP2002304386A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device capable of enhancing an input and output capability when it is in a microprocessor mode. SOLUTION: In the semiconductor device with input and output terminals having plural functional capabilities, as for a port incapable of inputting and outputting the data because the port is used for an address bus, a data bus and a control signal when it is in a microprocessor mode to access an outside memory, a resister 4 to hold the data is provided, and the contents of the resister 14 are inputted and outputted to and from plural ports other than the port in the used condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a port emulation function of input / output terminals in a semiconductor integrated circuit including a microcomputer.

[0002]

2. Description of the Related Art FIG. 5 shows a memory connection in a microprocessor mode in the prior art. Where 1
Denotes a microcomputer having peripheral circuits such as a CPU, a ROM, a RAM, and a timer (hereinafter, referred to as a microcomputer);
Is an external memory connected to the outside of the microcomputer 1, 3 is an address bus, 4 is a data bus, 5 is a control signal circuit, and the microcomputer 1 and the external memory 2 are an address bus 3, a data bus 4, a control signal It is connected by a circuit 5.

The connection shown in FIG. 5 is an example when the external memory 2 is a ROM. Address data and signals output from the microcomputer 1 are received by the external memory 2 via the address bus 3 and the control signal 5, and data is transmitted from the external memory 2 to the microcomputer 1 via the data bus 4.

FIG. 6 is a simplified diagram of an internal input / output function in a microprocessor mode in the prior art.
In FIG. 6, internal circuits such as a CPU are omitted. Here, 1 is a microcomputer having peripheral circuits such as a CPU, ROM, RAM, and timer, 3 is an externally connected address bus,
4 is an externally connected data bus, 5 is an externally connected control signal circuit, 6 is a multifunction input / output port circuit having an address bus and a port function, and 7 is a multifunction input / output having a data bus and a port function. A port circuit, 8 is a multi-function input / output port circuit having a control signal circuit and a port function, 9 is a normal input / output port circuit, 10 is an input / output circuit of an externally connected port, and 11 is an input / output port circuit 9. A register called a port latch for holding data, and a system bus 12 comprising an address bus, a data bus, and a control signal circuit inside the microcomputer.

[0005] As an input / output operation of the microcomputer, when data is output, data supplied to the port circuit 9 from the CPU via the system bus 12 is output to the outside 10 via the register 11. When inputting data, the input data 10 is stored in the register 1 of the port circuit 9.
Hold at 1. Register 11 of each port circuit 9
Is given an address, and the CPU fetches data by referring to the register 11 using the address.

In the microprocessor mode, the multi-function input / output port circuit 6 having an address bus and a port function is forcibly connected directly to the address bus of the system bus 12 to form a multi-function input / output circuit having a data bus and a port function. I / O port circuit 7
Is forcibly connected directly to the data bus of the system bus 12, and the multi-function input / output port circuit 8 having control signals and port functions is forcibly connected to the system bus 12.
Is directly connected to the data bus. Therefore, these input / output ports of the multifunction function are used for accessing an external memory and cannot be used as ordinary ports.

[0007]

In the prior art,
With such a configuration, when the operation of a microcomputer normally used in a single-chip mode by a customer is checked using an external ROM in a microprocessor mode, such as failure analysis, the microcomputer is assigned to an address bus and a data bus. I couldn't see the output of the terminal where it was.

An object of the present invention is to provide a semiconductor device having an input / output terminal having a plurality of function functions and capable of improving the input / output function in a microprocessor mode.

[0009]

According to a first aspect of the present invention, there is provided a semiconductor device having a plurality of function functions at input / output terminals.
For ports that cannot be used for data input / output because they are used as data buses and control signals, register means for holding the data is provided, and the contents of the register means are input / output from ports other than the ports in use. It is something to do.

In a semiconductor device according to a second aspect of the present invention, a semiconductor device having a plurality of function functions at input / output terminals is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. For ports that cannot input / output data because of the port being set, register means for holding the data is provided, and the contents of the register means are input / output from a plurality of ports other than the ports in use. is there.

In a semiconductor device according to a third aspect of the present invention, a semiconductor device having a plurality of function functions at input / output terminals is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. A plurality of register means for holding the data is provided for a port which cannot input / output data because the port has been set, and the contents of the plurality of register means are input / output from one port other than the port in use. It was made.

According to a fourth aspect of the present invention, in the semiconductor device having a plurality of function functions at the input / output terminals and having serial input / output means, the address bus and the data bus are provided in a microprocessor mode for accessing an external memory. A register means for holding data is provided for a port which cannot be used for data input / output because it is used for a control signal, and the contents of the register means are input / output using the serial input / output means. It was done.

According to a fifth aspect of the present invention, in the semiconductor device having a plurality of function functions at input / output terminals, the semiconductor device is used as an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. For a port that cannot input / output data because of the connection, register means for holding the data and dedicated serial input / output means are provided in the register means, and the contents of the register means are sent from the dedicated serial input / output means. Is input and output.

According to a sixth aspect of the present invention, in the semiconductor device having a plurality of function functions at input / output terminals, the semiconductor device is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. Register means for holding system bus side data of an address bus, a data bus, and a control signal which cannot be input / output with respect to a port which cannot input / output data because the port cannot be input / output. In addition to inputting / outputting the contents of the means, normal port input / output is directly input / output from the port in use.

In the semiconductor device according to a seventh aspect, the setting for shifting to the input / output operation by the port emulation function according to the first to sixth aspects is performed by a terminal setting executed at the time of reset. .

In the semiconductor device according to an eighth aspect of the present invention, the selection of the input / output ports in the third to fifth aspects is performed by the terminal setting executed at the time of resetting. is there.

In the semiconductor device according to the ninth aspect, the setting for shifting to the input / output operation by the port emulation function in the first to sixth aspects is made by the value of the command input at the time of reset. .

In the semiconductor device according to the tenth aspect, the third device
According to the fifth aspect of the present invention, the setting of the input / output port that can be input / output is performed by the value of the command input at the time of resetting.

In the semiconductor device according to the eleventh aspect, the third
According to the sixth aspect of the present invention, the setting of the input / output ports that can be input / output is such that the unused terminals are used to switch which port is set as the input / output port.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram showing the configuration of the port emulation circuit according to the first embodiment. Embodiment 1 corresponds to the first and second inventions.

In the figure, 1 is a CPU, ROM, RA
M, a microcomputer having a peripheral circuit such as a timer, 3 an externally connected address bus, 4 an externally connected data bus, and 5 an externally connected control signal circuit. 6 is a multifunction input / output port circuit having an address bus and a port function, 7 is a multifunction input / output port circuit having a data bus and a port function, and 8 is a multifunction input / output port circuit having a control signal and a port function. , 9 are ordinary input / output port circuits, and 10 is an input / output circuit of a port connected externally. Reference numeral 11 denotes a register called a port latch for holding data in the input / output port circuit 9, reference numeral 12 denotes a system bus comprising an address bus, data bus, and control signal circuit inside the microcomputer, and reference numeral 13 denotes a bus for realizing the present invention. 14 shows a register having an address decoder added to implement the present invention. In FIG. 1 showing the first embodiment, a register 14 of an input / output port circuit 13 is added to the conventional technology shown in FIG.

In FIG. 1, the address decoder of the newly added register 14 is given the same address as the address decoder of the register at the multi-function input / output ports 6 to 8, so that the output from the microcomputer is controlled. Although the same value is written to the newly added register 14, the data may collide with an external input.
4 is in an unusable state.

When the first and second embodiments are selected in the microprocessor mode, the multifunction input / output port circuits 6 to 8 are used as address bus control signals for accessing an external memory. , Multifunction input / output port circuit 6
The address decoders of the registers of .about.8 cannot be used. Then, the address decoder of the newly added register 14 becomes usable, and the function of the port that cannot be used for input / output because it has been used as an address bus and data bus control signal is input / output from the port 13 to which the circuit is added. However, in this case, since input / output is performed through the added port 13, data cannot be input / output through the original register 11. As described above, in an actual circuit, a port latch having an address decoder is added to a port circuit portion, and the first and second port latches 11 and the newly added port latch 14 are switched and used. An embodiment according to the present invention is realized.

According to the first embodiment of the present invention, in a semiconductor device having a plurality of function functions at input / output terminals, an address bus, a data bus, and a data bus are provided in a microprocessor mode for accessing an external memory.
For a port that cannot be used for data input / output because it is used for a control signal, register means 14 is provided which constitutes a port latch for holding the data. 14 so that the register means 1 can be accessed from a plurality of ports other than the ports in use.
By inputting and outputting the contents of No. 4, a semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

Embodiment 2 Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is an explanatory diagram showing the configuration of the port emulation circuit according to the second embodiment. The second embodiment corresponds to the third invention.

In the figure, 1 is a CPU, ROM, RA
M, a microcomputer having a peripheral circuit such as a timer, 3 an externally connected address bus, 4 an externally connected data bus, and 5 an externally connected control signal circuit. 6 is a multifunction input / output port circuit having an address bus and a port function, 7 is a multifunction input / output port circuit having a data bus and a port function, and 8 is a multifunction input / output port circuit having a control signal and a port function. , 9 are ordinary input / output port circuits, and 10 is an input / output circuit of a port connected externally. Reference numeral 11 denotes a register called a port latch for holding data in the input / output port circuit 9, reference numeral 12 denotes a system bus constituted by an address bus, data bus, and control signals inside the microcomputer, and reference numeral 15 denotes a bus for realizing the present invention. Input / output port circuits 16 and 17 with additional circuits indicate registers having an address decoder added to implement the present invention. In FIG. 2 showing the second embodiment, registers 16 and 17 of an input / output port circuit 15 are added to the conventional technology shown in FIG.

In FIG. 2, similarly to the first embodiment, the address decoders of the newly added registers 16 and 17 are given the same addresses as the address decoders of the registers at the multifunction input / output ports 6 to 8, respectively. The same value is written to the newly added registers 16 and 17 for the output from the inside of the microcomputer. However, since data collide at the time of input from the outside, usually, the newly added register 14 is used. The address decoder cannot be used. When the embodiment according to the third invention is selected in the microprocessor mode, the multifunction input / output port circuits 6 to
Reference numeral 8 is used as an address bus control signal for accessing an external memory, and the address decoder of the register in the multifunction input / output port circuits 6 to 8 cannot be used. And the newly added register 1
One of the address decoders 6 and 17 can be used, and the function of a port that cannot be used for input / output because it is used as an address bus and data bus control signal is input / output from the port 15 to which a circuit is added. However, in this case, among the plurality of registers 11, 16, and 17, only the selected register can be used, and the value of the original register 11 and the value of the unselected register cannot be input / output. As described above, in the actual circuit, a plurality of port latches having an address decoder are added to the port circuit portion, and the port latch 11 which is originally provided and the plurality of newly added port latches 16 and 17 are switched and used. An embodiment according to the third invention is realized.

According to the second embodiment of the present invention, in a semiconductor device having a plurality of function functions at input / output terminals, an address bus, a data bus, and a data bus are provided in a microprocessor mode for accessing an external memory.
A plurality of register means 16 and 17 constituting a port latch for holding the data are provided for a port that cannot be used for data input / output because it is used for a control signal, and one port other than the used port is provided. The input / output of the contents of the plurality of register means 16 and 17 is performed by inputting / outputting the contents of the plurality of register means 16 and 17 from one port other than the port in use. Register means 16, 17
Accordingly, a semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

Embodiment 3 Third Embodiment A third embodiment according to the present invention will be described with reference to FIG. FIG. 3 is an explanatory diagram showing the configuration of the port emulation circuit according to the third embodiment. The third embodiment corresponds to the fourth and fifth inventions.

In the figure, 1 is a CPU, ROM, RA
M, a microcomputer having a peripheral circuit such as a timer, 3 an externally connected address bus, 4 an externally connected data bus, and 5 an externally connected control signal circuit. 6 is a multifunction input / output port circuit having an address bus and a port function, 7 is a multifunction input / output port circuit having a data bus and a port function, and 8 is a multifunction input / output port circuit having a control signal and a port function. Reference numeral 9 denotes a normal input / output port circuit, and reference numeral 10 denotes an input / output circuit of an externally connected port. 11 is a register called a port latch for holding data in the input / output port circuit 9, 12 is an address bus inside the microcomputer,
A data bus, a system bus composed of control signals,
18 is an I / O circuit used to implement the present invention;
Reference numeral 19 denotes a register having an address decoder added to implement the present invention.

The serial I / O circuit 18 in FIG.
According to the fourth aspect, it is assumed that the serial I / O circuit is a built-in serial I / O circuit that can be used by the user and has a register 19 having an address decoder in advance. However, if all serial I / O circuits are used on the user side, this method cannot be used.

According to the fifth aspect of the present invention, a serial I / O having a register 19 having an address decoder is provided.
This is a serial I / O circuit that cannot be used by a user without adding a circuit to the user.

Although the fourth and fifth embodiments are the same circuit, there is a difference between the serial I / O circuit and the user open / closed state. In the case of the fourth aspect of the present invention, the input / output terminals are already open to the user, and in the case of the fifth aspect, the input / output terminals are newly provided.

In FIG. 3, the address decoder of the register 19 added to the serial I / O circuit has multi-function input / output ports 6 to similarly to the first embodiment.
8, the same address as that of the address decoder of the register 8 is given, and the same value is written in the newly added register 19 with respect to the output from the microcomputer, but the data hits at the time of input from the outside. Therefore, normally, the address decoder of the newly added register 14 cannot be used.

When the embodiment according to the fourth or fifth aspect of the present invention is selected in the microprocessor mode, the multifunction input / output port circuits 6 to 8 are used as address bus control signals to access an external memory. The used address decoders of the registers in the multi-function input / output port circuits 6 to 8 are disabled. Then, the address decoder of the newly added register 19 becomes effective, and one or more data of one or more ports which cannot be used for input / output because they have been used as address bus and data bus control signals are input / output from the serial I / O circuit 18. .

In the fourth and fifth embodiments, since serial I / O circuits are used, high-speed data cannot be input / output in real time, but the number of terminals used is small. There are advantages and more pins are available in microprocessor mode.

As described above, in an actual circuit, a plurality of port latches 19 having an address decoder are added to the serial I / O circuit 18 installed inside the microcomputer, and the original port latch 11 and a plurality of newly added ports are added. By switching and using the latch 19, the fourth and fifth latches are used.
An embodiment according to the present invention is realized.

According to the third embodiment of the present invention, in a semiconductor device having a plurality of function functions at the input / output terminals and having the serial input / output means 18, the address bus, the microprocessor, and the external memory are accessed in the microprocessor mode. For ports that cannot be used for data input / output because they are used for data buses and control signals, register means 19 for holding the data is provided.
Therefore, by inputting / outputting the contents of the register means 19 using the serial input / output means 18, it is possible to obtain a semiconductor device capable of improving the input / output function in the microprocessor mode. it can.

According to the third embodiment of the present invention, in a semiconductor device having a plurality of function functions at input / output terminals, an address bus, a data bus, and a control signal are provided in a microprocessor mode for accessing an external memory. For a port which cannot be used for data input / output because it is used for the purpose, a register means 19 for holding the data and a dedicated serial input / output means 18 are provided for the register means. The input / output of the contents of the register means 19 can be performed by inputting / outputting the contents of the register means 19 from the dedicated serial input / output means 18 to improve the input / output function in the microprocessor mode. Can be obtained.

Embodiment 4 FIG. Embodiment 4 of the present invention will be described with reference to FIG. FIG. 4 is an explanatory diagram showing the configuration of the port emulation circuit according to the third embodiment. The fourth embodiment corresponds to the sixth invention.

In the figure, 1 is a CPU, ROM, RA
M, a microcomputer having peripheral circuits such as a timer, 3 an externally connected address bus, 4 an externally connected data bus, and 5 an externally connected control signal. 6 is a multifunction input / output port circuit having an address bus and a port function, 7 is a multifunction input / output port circuit having a data bus and a port function, and 8 is a multifunction input / output port circuit having a control signal and a port function. , 9 are ordinary input / output port circuits, and 10 is an input / output circuit of a port connected externally. Reference numeral 11 denotes a register called a port latch for holding data in the input / output port circuit 9, reference numeral 12 denotes a system bus constituted by an address bus, a data bus, and a control signal inside the microcomputer.
Reference numerals 0, 21, 22 denote address buses, data buses, and input / output port circuits capable of outputting control signals, which are added to realize the present invention. Reference numeral 23 denotes a register added to realize the present invention. I have.

FIG. 4 showing the fourth embodiment is different from the conventional example shown in FIG. 6 in that an address bus for accessing an external memory,
Data buses and ports for outputting control signals are different, and corresponding input / output port circuits 20, 21, 22
Register 11 is added to the circuit.

In FIG. 4, the newly added register 2
Reference numeral 3 denotes a circuit having no address decoder. In the microprocessor mode, the address bus, data bus, and control signal data transmitted to the system bus are given in the same manner as the multifunction input / output port circuits 6 to 8, and the output from the microcomputer is newly added. The same value is also written to the registered register 23, but the data is collided at the time of input from the outside, so that the newly added register 23 is normally in an unusable state.

When the embodiment according to the sixth invention is selected in the microprocessor mode, the input / output port circuit 20 capable of outputting the added address bus is forcibly set via the register 23 to the address bus of the system bus 12. The input / output port circuit 21 which is directly connected to the system bus 12 and can output the added data bus is forcibly connected directly to the data bus of the system bus 12 via a register, and is capable of outputting the added control signal. Are forcibly connected directly to the control signal of the system bus 12 via a register, and access to an external memory is made from these ports. At this time, the multifunction input / output port circuits 6 to 8 cannot be used as an address bus, a data bus, or a control signal for accessing an external memory, and can be used only as a normal port. However, in this case, the ports 20, 21, 22 for inputting / outputting the system bus signal are used.
Cannot input / output the value of the register 11 originally.

As described above, in an actual circuit, the port latch 23 is added to the port circuit portions 20, 21, and 22,
The embodiment according to the sixth invention is realized as a switchable port for accessing an external memory.

According to the fourth embodiment of the present invention, in a semiconductor device having a plurality of function functions at input / output terminals, an address bus, a data bus, and a data bus are provided in a microprocessor mode for accessing an external memory.
For ports that cannot be used for data input / output because they are used for control signals,
Register means 23 for holding data bus and system bus side data of control signals is provided. The contents of the register means 23 are input / output from ports other than the ports in use, and normal ports are transmitted from the ports in use. Since the port input / output is directly input / output, the register means 23 is connected to a port other than the port in use.
By inputting / outputting the contents of the above, and inputting / outputting the normal port input / output from the port in use as it is, a semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

Embodiment 5 Embodiment 5 of the present invention will be described. The fifth embodiment corresponds to the seventh and eighth inventions. As a seventh embodiment of the present invention, a latch circuit for holding data in a port circuit is provided for a specific terminal in the circuits in the first to fourth embodiments having a port emulation circuit. The latch circuit operates in response to a reset signal. When the microcomputer is in a reset state, the latch circuit is in a data input state and holds data input to a terminal. When the reset state of the microcomputer is released, the latch circuit outputs data held in the reset state and uses a circuit configuration connected to the port emulation circuit.

For example, in the first to fourth embodiments, the microprocessor mode is set,
Further, when the terminal to which the latch circuit is added is input at "L", a normal microprocessor mode operation is performed. When the terminal is input at "H", the first to sixth aspects of the present invention are applied. The port emulation operation according to the embodiment is performed.

When it is necessary to select the output port, the above-mentioned latch circuit is provided for a plurality of terminals, and which port can be output can be set by the terminal setting in the reset state. .

According to the fifth embodiment of the present invention, the setting for shifting to the input / output operation by the port emulation function in any one of the first to fourth embodiments is changed by the terminal setting executed at the time of reset. As a result, it is possible to improve the input / output function in the microprocessor mode, and to obtain a semiconductor device in which the transition to the port emulation operation can be performed more accurately by setting the terminals.

According to the fifth embodiment of the present invention, the input / output port selection in the second or third embodiment is set by the terminal setting executed at the time of reset. As a result, an input / output function in the microprocessor mode can be improved, and a semiconductor device in which input / output ports can be selected more accurately by setting terminals can be obtained.

Embodiment 6 FIG. Embodiment 6 of the present invention will be described. The sixth embodiment corresponds to the ninth and tenth aspects.

According to the ninth and tenth aspects of the present invention, in the circuits according to the first to fourth embodiments in which a port emulation circuit is present, a signal connected to a specific port from each terminal is provided. A plurality of decoder circuits for inputting lines are prepared. A latch circuit that detects the rising edge of the output of each decoder circuit and outputs "H" is connected, and the output of this latch circuit is added to the next-stage decoder circuit as one of the input signal lines of the next-stage decoder circuit Connect. Similarly, a circuit connecting several stages of decoder circuits is installed. In this circuit, if the data input to the ports match, the next-stage decoder circuit becomes valid. A latch circuit similar to that of the fifth embodiment is provided at the last stage of the plurality of decoder circuits, and a circuit configuration for connecting to a port emulation circuit is used.

For example, in the first to fourth embodiments, when all commands input to a specific port at the time of resetting match in the microprocessor mode setting, the first to sixth aspects of the present invention are implemented. The port emulation operation in the embodiment. If the commands do not match, a normal microprocessor mode operation is performed. If it is necessary to select a port to output, add a circuit that allows the port to be selected according to the command content, or install a decoder circuit in a tree shape and specify which port It can be set whether output is possible.

According to the sixth embodiment of the present invention, the setting for shifting to the input / output operation by the port emulation function according to any one of the first to fourth embodiments is determined by the value of the command input at the time of resetting. As a result, it is possible to improve the input / output function in the microprocessor mode and obtain a semiconductor device capable of shifting to the port emulation operation more accurately by inputting a command.

Further, according to the sixth embodiment of the present invention, the setting of the port selection for input / output in the third or fourth embodiment is performed by the value of the command input at the time of reset. In addition to improving the input / output function in microprocessor mode,
It is possible to obtain a semiconductor device in which the setting of port selection for input and output can be accurately performed by command input.

Embodiment 7 FIG. Embodiment 7 of the present invention will be described. The seventh embodiment corresponds to the eleventh invention.

The oscillator circuit of the microcomputer oscillates using two terminals of the Xin and Xout terminals when an oscillator is used. However, when a pulse is directly input, it is possible to input only the Xin terminal. No terminal is used and Xout
The terminal becomes an unused terminal. In a microcomputer with a sub clock, the Xcin terminal and the Xcout terminal are used.
When a pulse is input, the Xcout terminal becomes an unused terminal. On the user side, the microcomputer is operated using an oscillator. However, when performing an operation check such as failure analysis, a direct pulse input is possible.

As an embodiment according to the eleventh invention,
Embodiment 1 in which a port emulation circuit exists
In the circuit according to the fourth embodiment, the unused terminals are made usable by the setting method according to the fifth or sixth embodiment. Then, by setting using these unused terminals, a port for outputting in real time is selected and switched. When one terminal is used, two ports can be switched in real time. When two terminals are used, four ports can be switched in real time.

According to the seventh embodiment of the present invention, the setting of the port that can be input / output in any one of the second to fourth embodiments is performed by selecting unused ports as input / output ports using unused terminals. Since the setting is switched, it is possible to improve the input / output function in the microprocessor mode, and to obtain a semiconductor device in which the setting of the port for input / output can be performed more accurately by the unused terminal.

In the embodiment according to the present invention, in the microprocessor mode, a register for holding data to be input / output from a port which cannot be input / output is prepared, and the address bus and the data bus used in the microprocessor mode are provided. Enable input / output on different ports for functions that cannot be input / output on function terminals.

Further, in the microprocessor mode, it is possible to make settings and to use terminals whose output contents could not be viewed. Furthermore, it is possible to cope with a case where it is impossible to analyze a defective product or check the operation in the microprocessor mode, and it is possible to shorten the time required for analyzing the defective product, checking the operation or testing, and performing a detailed investigation.

According to the embodiment of the present invention, the following effects can be obtained. According to the first, second, and fourth embodiments of the present invention, it is possible to input / output real-time contents from different ports in emulation mode. The terminal that could not be seen can be used.

According to the second and third embodiments of the present invention, it is possible to input / output only the data content of a necessary port for emulation, and even in the use of a small number of terminals, the setting can be made in the microprocessor mode. The setting of the terminal that could not be performed becomes possible.

According to the fifth and sixth embodiments of the present invention, the setting can be performed during the reset period, and the operations of the first to fourth embodiments are ensured when the reset is released.

According to the seventh embodiment of the present invention, the ports usable in the first to fourth embodiments can be switched in real time when reset is released.

[0067]

According to the first aspect of the present invention, in a semiconductor device having a plurality of function functions at input / output terminals, the semiconductor device is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. For ports that cannot input / output data because of the use of a port, register means for holding the data is provided, and the contents of the register means are input / output from ports other than the ports in use. By inputting / outputting the contents of the register means from a port other than the port in the state, a semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

According to the second invention, in the semiconductor device having a plurality of function functions at the input / output terminals, the semiconductor device is used as an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. For ports that cannot input or output data, register means for holding the data is provided, and the contents of the register means are input and output from a plurality of ports other than the ports in use. By inputting / outputting the contents of the register means from a plurality of ports other than the port in the state, a semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

According to the third aspect, in the semiconductor device having a plurality of function functions at the input / output terminals, the semiconductor device is used as an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. A plurality of register means for holding data is provided for a port that cannot input / output data because of the port, and the contents of the plurality of register means are input / output from one port other than the port in use. Therefore, by inputting / outputting the contents of the plurality of register means from one port other than the port in use,
A semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

According to the fourth aspect of the present invention, in a semiconductor device having a plurality of function functions at input / output terminals and having serial input / output means, an address bus, a data bus, and a control are provided in a microprocessor mode for accessing an external memory. For ports that cannot be used for data input / output because they are used for signals, register means for holding the data are provided, and the contents of the register means are input / output using the serial input / output means. By inputting / outputting the contents of the register means using the serial input / output means, a semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

According to the fifth aspect, in a semiconductor device having a plurality of function functions at input / output terminals, the semiconductor device is used as an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. For a port that cannot input / output data because of the presence of a port, register means for holding the data, and dedicated serial input / output means for the register means are provided,
Since the content of the register means is input / output from the dedicated serial input / output means, the input / output function of the register means is input / output from the dedicated serial input / output means, thereby improving the input / output function in the microprocessor mode. A semiconductor device that can be obtained can be obtained.

According to the sixth aspect, in a semiconductor device having a plurality of function functions at input / output terminals, the semiconductor device is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. Register means for holding the address bus, data bus, and control signal system bus side data which cannot be input / output for ports which cannot input / output data. While inputting / outputting the contents, normal port input / output is directly input / output from the port in use, so that the content of the register means is input / output from a port other than the port in use,
By directly inputting / outputting normal port input / output from the used port, a semiconductor device capable of improving the input / output function in the microprocessor mode can be obtained.

According to the seventh aspect, the first to sixth aspects are described.
Since the setting for shifting to the input / output operation by the port emulation function according to any one of the inventions is made by the terminal setting executed at the time of reset, the shift to the port emulation operation is made by the terminal setting executed at the time of reset. Thus, it is possible to improve the input / output function in the microprocessor mode, and to obtain a semiconductor device in which the transition to the port emulation operation can be performed more accurately by setting the terminals.

According to the eighth aspect, the third to fifth aspects are described.
In the setting of the port that can be input and output in any one of the inventions, the selection of the input / output port is performed by the terminal setting executed at the time of the reset. Accordingly, a semiconductor device can be obtained in which the input / output function in the microprocessor mode can be improved and the input / output port can be selected more accurately by setting the terminals.

According to the ninth aspect, the first to sixth aspects are described.
The setting for shifting to the input / output operation by the port emulation function according to any one of the inventions of the inventions is made by the value of the command input at the time of resetting. By doing so, it is possible to improve the input / output function in the microprocessor mode and obtain a semiconductor device capable of shifting to the port emulation operation more accurately by inputting a command.

According to the tenth aspect, the setting of the port selection for input / output in any one of the third to fifth aspects is performed by the value of the command input at the time of resetting. By setting the selection by the value of the command input at the time of resetting, it is possible to improve the input / output function in the microprocessor mode, and to obtain a semiconductor device in which the setting of the port selection for input / output can be made more accurately by the command input. it can.

According to the eleventh aspect, in the selection of a port capable of inputting / outputting in any one of the third to sixth aspects, the setting of which port is set as an input / output port using an unused terminal is performed. By switching the setting of the port selection that can be input and output using unused pins, the input / output function in the microprocessor mode can be improved, and the setting of the port selection that can be input and output can be changed by the unused pins. A semiconductor device which can be performed accurately can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a first embodiment according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a second embodiment according to the present invention.

FIG. 3 is an explanatory diagram showing a configuration of a third embodiment according to the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a fourth embodiment according to the present invention.

FIG. 5 is a block diagram showing a memory connection in a microprocessor mode according to the related art.

FIG. 6 is a simplified diagram of an internal input / output function in a microprocessor mode in a conventional technique.

[Explanation of symbols]

1 microcomputer, 2 external memory, 3 external address bus, 4 external data bus, 5 external control signal, 6 multifunction input / output port circuit (address bus / port), 7 multifunction input / output port circuit (data bus / port), 8 Multifunction input / output port circuit (control signal / port), 9 Normal input / output port circuit, 10 External input / output of normal input / output port, 1
1 added register circuit, 12 internal system bus, 13 input / output port circuit with added register, 14
Added register circuit, 15 register added I / O port circuit, 16, 17 added register circuit, 18 serial I / O circuit, 19 added register circuit, 20, 21, 22 added register I / O Port circuit, 23 Register circuit added.

Claims (11)

[Claims] In a semiconductor device having a plurality of function functions at an input / output terminal, data is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. 2. A semiconductor device, comprising: register means for holding data of a port which cannot be used, and inputting / outputting the contents of the register means from a port other than the port in use. 2. A semiconductor device having a plurality of function functions at an input / output terminal, which is used as an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. 2. A semiconductor device, comprising: register means for holding data for a port which cannot be used, and inputting / outputting the contents of the register means from a plurality of ports other than the ports in use. 3. A semiconductor device having a plurality of function functions at an input / output terminal, which is used as an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. A plurality of register means for holding data for a port which cannot be used, and the contents of the plurality of register means are input / output from one port other than the port in use. apparatus. 4. A semiconductor device having a plurality of function functions at an input / output terminal and having a serial input / output means, which is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. A port for which data cannot be input / output because of the presence of the serial input / output means. . 5. A semiconductor device having a plurality of function functions at an input / output terminal, which is used as an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. Register means for holding the data of the port which cannot be provided, and dedicated serial input / output means provided for the register means, and the contents of the register means are input / output from the dedicated serial input / output means. A semiconductor device characterized by the above-mentioned. 6. A semiconductor device having a plurality of function functions at an input / output terminal is used for an address bus, a data bus, and a control signal in a microprocessor mode for accessing an external memory. Register means for holding the address bus, data bus, and system bus side data of control signals which cannot be input / output for ports which cannot be input / output, and input / output the contents of the register means from ports other than the ports in use. A semiconductor device wherein normal port input / output is directly input / output from the port in use. 7. The semiconductor device according to claim 1, wherein the setting for shifting to the input / output operation by the port emulation function is performed by a terminal setting executed at reset. . 8. The semiconductor device according to claim 3, wherein the input / output port selection is set by a terminal setting executed at the time of resetting. . 9. The semiconductor device according to claim 1, wherein the setting for shifting to the input / output operation by the port emulation function is performed by a value of a command input at the time of resetting. . 10. The semiconductor device according to claim 3, wherein the input / output port selection setting according to any one of claims 3 to 5 is performed by a value of a command input at reset. 11. The input / output port selection setting according to any one of claims 3 to 6, wherein an unused terminal is used to switch which port is set as an input / output port. Semiconductor device.