Title:
SINGLE CHIP MICROCOMPUTER
Document Type and Number:
Japanese Patent JPS6431256
Kind Code:
A
Abstract:
PURPOSE:To observe the using state of an input and output terminal at the time of analyzing the operation of a device and to facilitate the analyzing operation by disposing another observing terminal from which a control signal indicating the using state of the input and output terminals is outputted. CONSTITUTION:At the time of propagating '0' on an internal bus 1 and '1' on an internal bus 2 (input state), when the control signal is set to '1', the gate of transfer gates 81, 82 is turned on, the gate of transfer gates 91, 92 is turned off and the output of input buffers 121, 122 is connected respectively to the internal bus 1, the internal bus 2. In this case, '1' is outputted to an input state observing terminal 4 and '0' is outputted to an output state observing terminal 5. Then, at the time of propagating '0' to the input and output terminal 6 and '1' to the input and output terminal 7 (output state), when the control signal is set to '0', the gate of the transfer gates 81, 82 is turned off, the gate of the transfer gates 91, 92 is turned on and the input of output buffers 131, 132 is connected to the internal bus 1 and the internal bus 2, respectively. In this case, '1' is outputted to the output state observing terminal 5 and '0' is outputted to the input state observing terminal 4.
Inventors:
KUDO MOTOFUMI
Application Number:
JP18817087A
Publication Date:
February 01, 1989
Filing Date:
July 27, 1987
Export Citation:
Assignee:
NEC CORP
International Classes:
G06F11/30; G06F15/78; (IPC1-7): G06F11/30; G06F15/06
Attorney, Agent or Firm:
Naoki Kyomoto (2 outside)