JP2002197055A - Semiconductor device with built-in interface - Google Patents

Abstract

(57) [Problem] To provide a configuration capable of improving an increase in circuit scale of a semiconductor device having two or more interface units. SOLUTION: A control circuit of an internal block of each interface unit is shared by one interface unit, and all the interface units are connected in a daisy chain. As a result, the internal circuit scale can be reduced, and the number of external terminals can be reduced by sharing the signal lines between the interface units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor device having a plurality of interfaces.

[0002]

2. Description of the Related Art Conventionally, in order to support a plurality of bus interfaces with one semiconductor device, an interface unit corresponding to each interface specification and a circuit for controlling various resources such as registers and memories inside the semiconductor device are provided. There is a need. FIG. 4 shows a conventional semiconductor device having at least two or more interface units.

The semiconductor device 1 shown in FIG. 4 has first to N-th interface units 2A, 2B,..., 2N, and an internal block 3 containing a register and a memory. Each of the interface units 2A to 2N includes a control circuit 4A, 4B,..., 4N for controlling the internal block 3.
have.

[0004] The interface section 2A has an external input terminal 5A and an external output terminal 6A. The interface section 2B has an input external terminal 5B and an output external terminal 6B. Hereinafter, similarly, the interface unit 2
N has an input external terminal 5N and an output external terminal 6N.

Next, an example of a system configuration of the conventional semiconductor device is shown in FIG. 5, and the prior art will be described. In the case of the system configuration of FIG. 5, the semiconductor device 1 and the CPU 8 that controls the semiconductor device 1 are connected via a bus 7. 9
Are external input terminals of the CPU 8 for controlling the semiconductor device;
0 is an output external terminal of the CPU 8.

In the semiconductor device 1, an input external terminal 5A and an output external terminal 6A of an interface section 2A are connected to a bus 7. The input external terminals 5B to 5N of the remaining interface units 2B to 2N are fixed to high or low,
Output external terminals 6B to of the interface units 2B to 2N
6N is an unused terminal (open).

When data is input to the semiconductor device 1, a data input command is issued from the CPU 8, and the data input command and input data are sent via the bus 7.
In the semiconductor device 1, the data input instruction and the input data are received from the input external terminal 5A of the interface unit 2A, and the data is transmitted to the internal block 3 through the control circuit 4A.

When data is output from the semiconductor device 1, a data output command is issued from the CPU 8 that controls the semiconductor device, and the data output command is sent via the bus 7. In the semiconductor device 1, the data output command is received from the input external terminal 5A of the interface unit 2A, and the control circuit 4A sends the data output command to the internal block 3.

The internal block 3 receives the data output command and sends data to be output to the interface unit 2A.
And the interface unit 2A outputs data according to the specifications of the bus 7.

As described above, when the semiconductor device 1 is connected to the bus 7, the input external terminals 5B to 5N and the output external terminals 6B to 6N of the interface units 2B to 2N are not necessary. Further, the control circuits 4B to 4N do not need to operate.

When the semiconductor device 1 and the CPU 8 communicate with each other by connecting to a bus having another specification, the communication is performed via any of the interface units 2B to 2N instead of the interface unit 2A.

[0012]

In such a conventional configuration, each of the interface units 2A to 2N is required so as to correspond to the specifications of various buses connecting the semiconductor device 1, and the interface units 2A to 2N are required. The control circuits 4A to 4N having equivalent functions are indispensable for the 2N, and each of the interface units 2A to 2N must have an external terminal. This has a problem that the circuit scale increases when designing a semiconductor device corresponding to a plurality of interfaces.

An object of the present invention is to provide a semiconductor device in which an interface unit to be used can be arbitrarily selected, and the circuit scale and the number of external terminals can be reduced.

[0014]

SUMMARY OF THE INVENTION The present invention provides at least two
By connecting one or more interface units in a daisy chain and setting the functioning interface units, it is possible to reduce the number of control circuits that previously had to have N control circuits to one control circuit, and to share external terminals in each interface unit. Therefore, the number of the external terminals can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor device with a built-in interface according to the first aspect of the present invention is a semiconductor device having a plurality of built-in interfaces capable of exchanging data with an internal block according to external input / output specifications. A first function unit that converts an input of an external specification into an internal specification and a second function unit that converts an input of an internal specification into an external specification
And a second interface unit having a first function unit for converting the input of the external specification to the internal specification and a second function unit for converting the input of the internal specification to the external specification. Connecting an external terminal to an external specification input of a first functional unit of the first interface unit, connecting an external terminal for output to an external specification output of a second functional unit of the first interface unit, The external specification input of the first function unit of the unit is connected to the internal specification output of the first function unit of the first interface unit, and the external specification output of the second function unit of the second interface unit is connected to the first specification. Connect to the internal specification input of the second function part of the interface part,
A control circuit for controlling the internal block is provided between the internal specification output of the first function unit of the second interface unit, the internal specification input of the second function unit of the second interface unit, and the internal block. In addition, an interface selector that can select an arbitrary interface by setting an external terminal is provided, and other interface units other than the specific interface unit selected by the interface selector are configured to pass the input data as it is. And

According to a second aspect of the present invention, there is provided a semiconductor device with a built-in interface according to the first aspect, wherein a specific interface section is selected by an external terminal logic without providing an interface selector. .

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a semiconductor device having at least two or more interface units. Semiconductor device 11
Are the first to Nth interface units 12A, 12B,
, 12N, an internal block 13 containing a register and a memory, and an interface selector 14.

The output signal 17 of the first interface unit 12 A connected to the input external terminal 15 and the output external terminal 16 of the semiconductor device 11 is supplied to the second interface unit 1.
2B, the output signal 18 of the second interface unit 12B is input to the first interface unit 12A.

An output signal 19 of the second interface unit 12B is input to a third interface unit at a subsequent stage.
The output signal 20 of the third interface unit is input to the second interface unit 12B.

Similarly, input / output signals are transmitted and received between the third interface section and the Nth interface section 12N. A control circuit 23 for controlling the internal block 13 is provided only in the N-th interface unit 12N connected to the internal block 13 among the interface units 12A to 12N. The output signal 21 is connected to the internal block 13, and the output signal 22 of the internal block 13 is connected to the Nth interface unit 12N.

The interface selector 14 is configured so that an arbitrary interface can be selected by setting an external terminal 24.
Select signals 25A, 2A, 12B,.
, 25N are supplied.

The first to Nth interface units 1
, 12N are the select signals 25.
A, 25B,..., 25N, the only specific interface unit performs an input / output signal conversion operation, and the other interface units except the specific interface unit output the input signal as it is. Have been. However, the Nth interface unit 12N
Is configured so that the function of the control circuit 23 operates even when it is not selected by the select signal 25N.

More specifically, the connection relationship between the first to Nth interface units 12A to 12N is configured as shown in FIG. Here, the first and second interface units 12A and 12B will be described as an example, but the same applies to other interface units.

The first interface unit 12A has a first function unit 31A for converting an input of an external specification into an internal specification and a second function unit 32 for converting an input of an internal specification to an external specification.
A. Second interface unit 12B
Has a first function unit 31B that converts an input of an external specification into an internal specification and a second function unit 32B that converts an input of an internal specification into an external specification.

The input external terminal 15 is connected to the external specification input 33 of the first functional unit 31A of the first interface unit 12A.
And the output external terminal 16 is connected to the external specification output 34 of the second function section 32A of the first interface section 12A.
It is connected to the.

The external specification input 35 of the first function unit 31B of the second interface unit 12B is the internal specification output 3 of the first function unit 31A of the first interface unit 12A.
6, the external specification output 37 of the second function unit 32B of the second interface unit 12B is connected to the internal specification input 38 of the second function unit 32A of the first interface unit 12A.
It is connected to the. An internal block 13 is provided between the internal specification output 39 of the first function unit 31B of the second interface unit 12B, the internal specification input 40 of the second function unit 32B of the second interface unit 12B, and the internal block 13. Is provided.

FIG. 3 shows a system configuration using the semiconductor device 11 configured as described above. The semiconductor device 11 and a CPU 8 that controls the semiconductor device 11 are connected via a bus 7. 9 is a CPU 8 for controlling the semiconductor device
Are external terminals for input of the CPU 8. In the semiconductor device 11, the input external terminal 15 and the output external terminal 16 of the interface unit 12A are connected to the bus 7, and the external terminal 24 is also connected to the bus 7.

First, the first to N-th interface units 1
It is assumed that the interface conforming to the specification of the bus 7 among the 2A, 12B,..., 12N is the first interface unit 12A.

When data is input to the semiconductor device 11, the CPU 8 connects the external terminal 24 via the bus 7 to the external terminal 24.
The first interface unit 12A is set and fixed so as to be selected as a specific interface unit. Thereby, the first interface unit 12A is selected in the semiconductor device 11 by the select signal 25A.

When a data input command is issued from the CPU 8, the data input command and input data are sent via the bus 7. The semiconductor device 11 that has received the data input command and the input data from the input external terminal 15 sends the input data to the second interface unit 12B via the first interface unit 12A, but the second interface unit 12B The first interface unit 12A is not selected by the interface selector 14
Is sent to the third interface unit as it is.

Similarly, the data is sequentially sent to the subsequent interface unit. In the interface unit not selected by the interface selector 14, the data received from the previous stage passes through as it is, and the control circuit 23 inside the N-th interface unit 12N sends the data to the internal block 13
Sent to

When outputting data from the semiconductor device 11, a data output instruction is issued from the CPU 8 and a data output instruction is sent via the bus 7. Semiconductor device 11 receiving a data output command from external input terminal 15
Is the same as the above, the first interface unit 12
A is sent to the second interface unit 12B via A,
The data is sent from the control circuit 23 to the internal block 13 through the second interface unit 12B to the N-th interface unit.

The internal block 13 that has received the data output command sends an output signal 22 of data to be output to the Nth interface unit 12N. This output data passes through the interface unit not selected. Finally, the data is sent to the first interface unit 12A, where the data is output according to the specifications of the bus 7.

As described above, the interface section can be selected and used according to the specification to which the semiconductor device is connected, and the circuit scale and the number of external terminals can be reduced.

In the above-described embodiment, the interface selector 14 is provided. However, the interface selector 14 may not be provided and a specific interface unit may be selected by logic of an external terminal.

[0036]

As described above, according to the semiconductor device with a built-in interface of the present invention, the interface section can be selected and used according to the specification to which the semiconductor device is connected, and the circuit scale can be reduced and the number of external terminals can be reduced. Reduction can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a semiconductor device according to an embodiment of the present invention;

FIG. 2 is a configuration diagram of an interface unit according to the embodiment;

FIG. 3 is a configuration diagram of a system using the semiconductor device of the embodiment;

FIG. 4 is a configuration diagram of a conventional semiconductor device with a built-in interface.

FIG. 5 is a configuration diagram of a system configuration using a conventional semiconductor device.

[Explanation of symbols]

Reference Signs List 11 semiconductor device with built-in interface 12A first interface section 12B second interface section 13 internal block 14 interface selector 15 input external terminal 16 output external terminal 23 control circuit 24 external terminal 31A first of first interface section 12A The first functional unit 32B of the second interface unit 12B The second functional unit 32B of the second interface unit 12B 33 The first functional unit 32B of the second interface unit 12B External specification input 34 External specification output of the second function unit 32A 35 External specification input of the first function unit 31B 36 Internal specification output of the first function unit 31A 37 External specification output of the second function unit 32B 38 Second Of the internal function of the first functional unit 31B Part Specification output 40 inside specifications input of the second functional unit 32B

Claims (2)

[Claims] 1. A semiconductor device having a plurality of built-in interfaces capable of exchanging data with an internal block according to an external input / output specification, wherein the first function unit converts an input of the external specification into an internal specification. A first interface unit having a second function unit for converting an input of an internal specification into an external specification, a first function unit for converting an input of an external specification into an internal specification, and converting the input of an internal specification into an external specification A second interface unit having a second function unit for conversion, an input external terminal connected to an external specification input of the first function unit of the first interface unit, and an output external terminal connected to the first external unit. To the external specification output of the second function unit of the interface unit, and connect the external specification input of the first function unit of the second interface unit to the internal specification output of the first function unit of the first interface unit. The external specification output of the second function unit of the second interface unit is output to the second interface unit of the first interface unit.
Between the internal specification input of the first function unit of the second interface unit, the internal specification input of the second function unit of the second interface unit, and the internal block. A control circuit for controlling the internal block, an interface selector capable of selecting an arbitrary interface by setting an external terminal, and other interface units other than the specific interface unit selected by the interface selector are provided with input data. Semiconductor device with a built-in interface that is configured to pass through as it is. 2. The interface built-in type semiconductor device according to claim 1, wherein a specific interface section is selected by logic of an external terminal without providing an interface selector.