JPH03225845A - Integrated circuit - Google Patents

Abstract

PURPOSE:To obtain a floating state without removing an integrated circuit such as an LSI from a substrate by bundling enable input terminals from each buffer into one terminal for forming a floating terminal and then by controlling this floating terminal. CONSTITUTION:A three-state control buffer part 5 is connected to an output part 4 within an LSI 1, it is at Low level normally within the LSI 1, and it performs normal operation when the power is turned on. A floating terminal 7 is set to High level through a cable 12 of an emulator connector 9 to set a floating state. Thus, each enable input of a three-state control buffer 6 at the buffer part 5 is set to High level and an output terminal 8b of the LSI 1 is in floating state. Thus, by setting the floating terminal 7 to High level, operation of the LSI 1, etc., can be turned into insulation state easily, thereby enabling operation check, etc., of a hardware to be performed without removing the LSI 1, etc.

Description

[Detailed description of the invention] Industrial applications The present invention relates to integrated circuits such as LSIs.

Conventional technology In recent years, advances in semiconductor technology have been remarkable, and AV equipment, OA
Small, high-performance, low-priced high-tech products in the field of equipment, HA equipment, etc. are appearing one after another. Integrated circuits such as LSIs have made it possible to realize these high-tech products.

Conventionally, this type of LSI has been used by being mounted on a board together with other electronic components, and has been designed to become operational unconditionally by applying a voltage to a VCC terminal or a GND terminal.

Problems to be Solved by the Invention However, in such an LSI, when it is desired to make the LSI in an insulated state for checking the operation of the hardware, etc., the LSI must be removed from the board or the power supply terminal must be cut off to make it in the insulated state. The problem was that I couldn't do it. Furthermore, when connecting an emulator that operates in the same way as a CPU on the hardware, there is a problem in that the CPU must be removed from the board.

The present invention solves these conventional problems,
It is an object of the present invention to provide an excellent integrated circuit that can be placed in a floating state without removing the integrated circuit such as an LSI from a substrate.

Means for Solving the Problems In order to achieve the above object, the present invention provides a three-state control buffer at each output section inside an integrated circuit such as an LSI, and also connects each enable input of each three-state control buffer to -. They are collectively used as floating terminals.

Operation Therefore, according to the present invention, the floating terminal is
By setting it to the high level, the operation of the LSI etc. can be easily brought into an insulated state, and the operation of the hardware can be checked without removing the LSI etc., which is advantageous.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, ■ is an LSI, 2 is an input section inside LS11, and 3 is -1? Section a, 4, is an output section. 5 is LS
The buffer section 7 includes a three-state control buffer 76 that controls the output signal inside the ll. Reference numeral 7 designates a floating terminal which collects each enable force of each three-state capital control buffer 6 into a floating state by controlling the buffer unit 5. 8a is an input terminal, and 8b is an output terminal.

The floating terminal 7 is connected to the LSI 1 as shown in FIG.
A connector 9 of an ICE (in-circuit emulator) is placed over the floating terminal 7 and connected to the floating terminal 7 . Then, by setting the floating terminal 7 to High level (5V), LSll becomes a floating state.

Next, the connection method in the above embodiment will be explained. As shown in FIG. 3, the LSII is mounted on a substrate 10. Then, the emulator connector 9 is placed on top of this LSII. A floating connection pin 11 that can be connected to the floating terminal 7 of LSII is provided on the back side of the emulator connector 9. After connecting this connection pin 11 to the floating terminal 7 of LSII,
Connect the 70-teink terminal 7 to H1gh through the cable 12.
By setting the LSll to its output terminal 8b
It does not output any output signal and becomes insulated. Note that there is a pin contact terminal 1 on the inside of the back side of the emulator connector 9.
3 comes into contact with each input/output terminal pin 8 of the LSII.

Next, the operation of the above embodiment will be explained. A three-state control buffer section 5 is connected to the output section 4 inside the LS 11, and is normally at a low level inside the LS 11, and performs normal operation when the voltage is turned on. To set the floating state, by setting the floating terminal 7 to High level through the cable 12 of the emulator connector 9, each enable input of the three-state control buffer 6 of the buffer unit 5 becomes High, and the LS
The rl output terminal 8b is in the 70-ting state.

As described above, according to the embodiment, by providing the 70-ting terminal 7 in the LSII, the LSI output signal can be easily brought into a floating state. Therefore, when output signals overlap each other due to a hardware operation check, etc., by sequentially setting each LSI to the 70-ting state, it is possible to determine which LSI's signal is the cause. Furthermore, C on the hardware
When connecting an emulator that operates in the same way as a PU, etc.,
Connect the emulator connector 9 with +5V floating connection pin 11 to LSll without removing the CPU on the board 10.
This has the advantage that the LSll can be placed in a floating state and virtual operations can be performed through an emulator.

Effects of the Invention As is clear from the embodiments described above, the present invention provides three-state control buffers at each output section inside the integrated circuit, and combines the enable inputs of these buffers into one terminal as a floating terminal. By controlling the floating terminals, integrated circuits such as LSIs can be placed in a floating state without removing them from the substrate. Fig. 1 is a schematic block diagram of an LSI according to an embodiment of the present invention, and Fig. 2 is the same. FIG. 3 is a perspective view of the external appearance of the LSI and the emulator connector, and FIG. 3 is a schematic cross-sectional view showing an example of the connection between the LSI and the emulator connector.

1... LSI, 2... Input section, 3... Control section, 4
... Output section, 5... Three-state control buffer section, 6... Three-state control buffer, 7... 70
-Ting terminal, 8... Input/output terminal pin, 8a...
Input terminal, 8b... Output terminal, 9... Emulator connector, 10... Board, 11... Floating connection pin, 12... Cable, 13... Pin contact terminal.

Claims (1)

[Claims] A three-state control buffer is provided in each output section within the integrated circuit, each enable input of each of the three-state control buffers is combined into one terminal as a floating terminal, and control operations can be isolated by controlling the floating terminal. integrated circuit.