Title:
INPUT/OUTPUT CIRCUIT FOR SIGNAL PROCESSOR
Document Type and Number:
Japanese Patent JPS62177601
Kind Code:
A
Abstract:
PURPOSE:To attain the effective use of terminals for digital input and output signals DI and DO by deciding whether a terminal is defined as input or output through an action mode setting operator and also performing the same defining action through a CPU based on the information on the decision of the setting operator. CONSTITUTION:A CPU 10 sets an input/output interface selection signal 19 at a high level to activate an input processing interface 13 after accepting the signal that defines the signals DI and DO as the DI from a keyboard 11. Here a photocoupler 16-b is always kept ON to short and open the DI/DO terminal and a COM terminal. Thus a photocoupler 16-a is turned ON and OFF for transmission of the input signal supplied from outside to the CPU 10. When a command defining the DI and DO as the DO is received from the keyboard 11, the signal 19 is set at a low level and an output processing interface 14 is activated. Thus the DI/DO terminal can be set under a programmable state with addition of the signal 19.
Inventors:
SAITO KOJI
Application Number:
JP1794786A
Publication Date:
August 04, 1987
Filing Date:
January 31, 1986
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G05B15/02; G06F13/12; (IPC1-7): G05B15/02; G06F13/12
Domestic Patent References:
| JPS54123690U | 1979-08-29 | |||
| JPS60106632U | 1985-07-20 | |||
| JPS57170733U | 1982-10-27 |
Attorney, Agent or Firm:
Katsuo Ogawa