Circulating shift register time-keeping circuit
AssigneeHewlett-Packard Company
InventorsFrance Rode, Eric A. Slutz
Life of this patent
Estimating the term…
Abstract
The circulating shift register time-keeping circuit of the present invention comprises five circulating shift registers and controller and time base circuits to provide real-time, stopwatch, date and alarm functions to an eight-digit display means via a display register. The real-time, stopwatch and date registers each include a binary adder, adder controller and auxiliary register coupled to clocked delay elements. The alarm register includes a comparator coupled to similarly clocked delay elements. Timing and command signals are provided to the five shift registers from the time base and controller, respectively.
Claims11
A circulating shift register time-keeping circuit comprising:
- timing means for producing a plurality of timing signals;
- control means for producing a plurality of control signals;
- storage means having a circulating shift register memory for storing time data representing progressively larger units of time, said time data circulating in the memory at a preselected rate in response to timing signals from the timing means, a binary adder coupled to the memory for incrementing the time data circulating therein, an auxiliary register coupled to the memory for storing incremented time data therein, and an adder controller coupled to the binary adder and auxiliary register and responsive to timing and control signals from the timing and control means, respectively, for causing the binary adder to periodically increment the time data representing the smallest unit of time circulating in the memory and to periodically increment the time data representing remaining progressively larger units of time circulating in the memory when the time data representing the largest preceding unit of time relative thereto equals preselected values and for causing the auxiliary register to modify the value of the incremented time data stored therein when that time data equals said preselected values;
- and
- display means coupled to the storage means for displaying the time data stored therein.
A real-time time data storage register comprising:
- a circulating shift register memory for storing time data representing progressively larger units of time, said time data circulating therein at a preselected rate in response to timing signals provided thereto;
- a binary adder coupled to the memory for incrementing the time data circulating therein;
- an auxiliary register coupled to the binary adder for storing the incremented time data received therefrom;
- an adder controller, coupled to the binary adder, the auxiliary register and responsive to timing and control signals for causing the binary adder to periodically increment the time data representing the smallest unit of time circulating in the memory, and to periodically increment the time data representing remaining progressively larger units of time circulating in the memory when the time data representing the largest preceding unit of time relative thereto equals preselected values, and for causing the auxiliary register to modify the value of the incremented time data stored therein when that time data equals said preselected values;
- and
- an output port connected to the circulating shift register memory for coupling time data therefrom.
Dependencies are inferred from the claim text.