Method for controlling an instrument panel display

• US 4,404,648 A
• Filed: 07/10/1979
• Issued: 09/13/1983
• Est. Priority Date: 07/19/1978
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Miyakawa, Nobuaki, Miki, Masayuki
• Primary Examiner(s): Chan, Eddie P.
• Application Number:
  US06/056,224
• Time in Patent Office: 1,526 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 364/565, 364/556, 364/431, 364/424, 364/484, 235/92 NT, 235/92 FQ, 235/92 DP, 235/92 TF, 324/160, 324/166, 377/2, 377/17, 377/19
• US Class Current: 702/176
• CPC Class Codes: G01D 5/244 influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
• CPC Class Codes: G01D 7/02 Indicating value of two or more variables simultaneously
• CPC Class Codes: G01P 1/08 Arrangements of scales, pointers, lamps or acoustic indicators, e.g. in automobile speedometers
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/2834 Automated test systems [ATE]; using microprocessors or computers G01R31/317 takes precedence; ATE for detection of defective computer hardware G06F11/2736
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09G 2360/04 Display device controller operating with a plurality of display units

Abstract

In a system for displaying a plurality of parameters, such as on an instrument panel of a vehicle, a plurality of signals in the form of pulses each having a pulse frequency corresponding to a respective parameter are generated by respective sensors. Each pulse supplied from these signals to a status register results in generation of an interrupt request signal to a central processing unit. The central processing unit controls a mask register which in turn controls a gating arrangement which selectively masks or inhibits the application of pulses from one or more sensors to the status register so that upon receiving a first interrupt request signal, the central processing unit can mask all sensors but the one responsible for the interrupt request signal and proceed with calculation of the parameter associated therewith by measuring the interval between subsequently-generated interrupt request signals, such measurement being carried out by execution of increment instructions. Internal timing and the use of flags provides for the calculation of successive values of different parameters and the periodic display thereof.

Claims

1. A method for controlling a display system for displaying a plurality of calculated values including a plurality of sensing means for generating a plurality of signals each consisting of a series of pulses at a frequency proportional to a respective one of said values to be calculated and a plurality of display means each provided for display of a respective one of said calculated values, the method comprising

(a) generating an initial interrupt request signal in response to receipt of a pulse from any one of said plurality of signals;

(b) detecting which one of the sensing means has provided the pulse resulting in generation of said initial interrupt request signal;

(c) masking the sensing means other than said one detected sensing means to prevent pulses from all but said one sensing means from generating interrupt request signals;

(d) generating a second interrupt request signal in response to receipt of a second pulse from said one sensing means;

(e) generating a third interrupt request signal in response to receipt of a third pulse from said one sensing means;

(f) measuring the interval between said second and third interrupt request signals;

(g) calculating a value based on said measured interval;

(h) storing the value resulting from said calculating step;

(i) removing the masking of said sensing means;

(j) repeating the steps (a) through (g) and (i) to store other values relating to signals generated by the other sensing means;

(k) counting a predetermined time interval in response to said initial interrupt request signal,

(l) generating a final interrupt request signal at the end of said predetermined time interval; and

(m) displaying said stored values in said respective display means in response to said final interrupt request signal.

2. A method for controlling a display system as claimed in claim 1, wherein said measuring step is performed by the execution of increment instructions by a central processing unit.

3. A display system for displaying a plurality of measured values comprising

a plurality of sensing means for generating a plurality of signals each consisting of a series of pulses at a frequency proportional to a respective one of said values;

a status register having a plurality of stages each individually settable by an applied pulse;

gate means for selectively connecting the output signal of each sensing means to a respective stage of said status register;

a mask register for controlling said gate means to selectively mask one or more output signals from said sensing means by preventing said signals from being applied to said status register;

interrupt request generating means for generating an interrupt request signal each time any one of the stages of said status register is set;

central processing means responsive to interrupt request signals for controlling said mask register to control said gate means so that said interrupt request generating means receives pulses from only one sensing means during successive periods of time and for measuring the intervals between interrupt request signals from the one sensing means in each of the successive periods for calculating measured values to be displayed;

a plurality of display means responsive to said central processing means for displaying said calculated measured values; and

counter means controlled by said central processing means for setting a stage of said status register at periodic intervals, said central processing means being responsive to an interrupt request signal generated as a result of said counter means for applying said calculated measured values to said display means.

4. A display system as claimed in claim 3, wherein said central processing means effects measurement of the intervals between interrupt request signals by execution of increment instructions.

5. A display system as claimed in claim 3, wherein said central processing means includes storage means for storing said calculated measured values and a plurality of flags and means for controlling the designation of the sensing means to be masked during said successive periods on the basis of said stored flags.

6. A display system as claimed in claim 3, wherein said display means each include a display device and a driver circuit for said display device, said calculated measured values being applied directly to said driver circuits from said central processing means.