JPH0511889A - Initializing circuit for data processor - Google Patents

Abstract

PURPOSE:To decrease the number of input/output pins of an LSI. CONSTITUTION:This circuit consists of a switch circuit 2 composed of plural switches, a switch condition holding circuit 3 which holds the states of the respective switches of the switch circuit corresponding to the switches, an initializing register 5 to which the output of the switch condition holding circuit 6 is connected by a shift path, and a reset/shift control circuit 1 which performs the resetting operation and shift control of the switch condition holding circuit and initial setting register, and the initial setting register and condition setting circuit are included in the same integrated circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an initial setting circuit of a data processing device composed of an integrated circuit.

[0002]

2. Description of the Related Art Generally, initial setting in a conventional data processing apparatus is performed by loading an initial microprogram at power-on and then setting internal apparatus conditions by the microprogram. At this time, some conditions are outside the integrated circuit (LSI). The state of the switch arranged in the above was directly taken into the LSI and used as the setting condition.

[0003]

In this conventional data processing device initial setting method, if the externally arranged switch conditions increase, the input / output pins of the LSI are used correspondingly, and the LSI is limited by the pin limit. There is a problem in that the cost cannot be increased or the cost cannot be increased because there is no choice but to use an LSI having more pins.

Conventionally, when a logic miss in the LSI is found, the design is generally redesigned. However, especially in the fault detection function having many logic misses, it is possible to previously control the deterrent condition from outside the LTI. In many cases, this can be avoided, and in this case as well, it was necessary to increase the pins of the LSI.

[0005]

An initial setting circuit of a data processing apparatus according to the present invention comprises a switch circuit composed of a plurality of switches, and a switch condition holding unit for holding the state corresponding to each switch of the switch circuit. A circuit, an initial setting register to which the output of the switch condition holding circuit is connected by a shift path, a condition setting circuit in which the output of the initial setting register is an input condition, a reset operation of the switch condition holding circuit and the initial setting register, and A reset / shift control circuit for performing shift control, and the initial setting register and the condition setting circuit are included in the same integrated circuit.

[0006]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

A reset / shift control circuit 1 is connected to the switch condition holding circuit 2 and the initial setting register 5 via a signal line 101. Reference numeral 2 is a switch circuit including a plurality of switches, and a signal line 102 of each switch is connected to a switch condition holding circuit 3 including a shift register.

The shift output 10 of the switch condition holding circuit 3
3 is connected to the shift-in of the initialization register 5 composed of a shift register, and the output 10 of the initialization register 5
4 is input to the condition setting circuit 6.

The integrated circuit 4 may be configured to include the initial setting register 5 and the condition setting circuit 6, and the reset / shift control circuit 1 may be included in the integrated circuit 4.

Next, the operation will be described.

It is assumed that each switch of the switch circuit has been set manually in advance. Following the power-on of the device, the reset / shift control circuit 1 resets the switch condition holding circuit 3 and the initialization register 5, and the subsequent operation of the reset / shift control circuit causes the state of the switch circuit 2 to change. The shift operation is activated by the control of the reset / shift control circuit 1, and the contents of the switch condition holding circuit 3 are transferred to the initial setting register 5.

The output 104 of the initial setting register 5 becomes the input of the condition setting circuit 6 together with other various conditions 105.
After that, the device operates under this condition.

FIG. 2 is a diagram in which the external condition taking-in operation by the switch shown in FIG. 1 can be suppressed as necessary.
An additional switch circuit shown by 7 is added to FIG. 1, and the state signal 106 thereof is connected to the reset / shift control circuit 1.

The switch of the additional switch circuit is set in advance manually or the like, and works to suppress the reset operation and the subsequent steps of the series of control operations performed by the reset / shift control circuit when the power of the apparatus is turned on.

[0016]

As described above, according to the present invention, the initial setting conditions given from the outside of the LSI are fetched into the shared shift register and set in the LSI by the shift operation, so that the input / output pins of the LSI are greatly reduced. However, it has an effect of contributing to cost reduction. Further, there is an effect that a measure for avoiding a logic error is put in the LSI in advance and it can be effectively used.

[Brief description of drawings]

FIG. 1 shows a block diagram of one embodiment of the present invention.

FIG. 2 shows a block diagram of another embodiment of the present invention.

[Explanation of symbols]

1 Reset / shift control circuit 2 switch circuits 3 switch condition holding circuit 4 integrated circuits 5 Initial setting register 6 Condition setting circuit 7 Additional switch circuit

Claims (2)

[Claims] 1. A switch circuit composed of a plurality of switches, a switch condition holding circuit that holds the state of each switch of the switch circuit, and an output of the switch condition holding circuit are connected by a shift path. An initial setting register, a condition setting circuit in which the output of the initial setting register is an input condition, a reset operation for performing a reset operation and shift control of the switch condition holding circuit and the initial setting register
And a shift control circuit, wherein the initial setting register and the condition setting circuit are included in the same integrated circuit. 2. An additional switch circuit, the output of which is connected to a reset / shift control circuit, for suppressing shift operation control from the switch condition holding circuit to the initial setting register by the reset / shift control circuit. The initialization circuit of the data processing device according to claim 1.