Method and apparatus for addressing a digital memory
First Claim
1. A method for addressing a central memory for interrogation thereof and retrieval of data stored therein, said addressing taking place in dependence on the operational states of a system which is itself controlled by the data in said central memory, at least one of said operational states being dependent on another state, preferably the temperature of the system, and in particular adapted to controlling an electronic fuel injection system for generating a correction frequency by using the data retrieved from said central memory, for processing by a main processor and for generation of injection pulses to control the opening times of fuel injection valves of the engine, the improvement comprising:
- deriving switching signals from prevailing operational states of the system and feeding said switching signals to a decoder circuit, cyclically activating said decoder for generating a single pre-address selector signal corresponding to each combination of operational states, said pre-address selector signal being fed to an address memory for generating a digital address, a first part of which is fed directly to said main processor for selecting an address range and a second portion of which being fed to a counter which is thereby set to an initial value, gating said counter for a predetermined length of time, feeding to said counter a clock pulse train dependent on said operational state of the system, thereby causing said counter to count upwardly from its initial value, and delivering the final contents of said counter at the expiration of said gating time to said central memory for providing the complete address therein, and closing the gating input to said counter if a particular combination of operational states is independent of said other operational state.
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Abstract
A central digital memory contains data relating values of operational variables of an installation to values of a stored parameter. The central memory is addressed in parallel via input lines carrying the address of the stored data. The address is generated by selecting one of several discrete input lines leading to an address selector memory which contains preliminary addresses related to the various operational states of the installation. A portion of the preliminary address is delivered directly to the central memory whereas another portion is used to preset a counter. If the particular operational state is dependent on another parameter, for example temperature, a temperature-dependent clocking frequency is admitted to the counter and alters its contents which are then used to supplement the first portion of the address already delivered to the central memory. If no temperature dependency exists, the second portion of the address is passed on without change.
15 Citations
25 Claims
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1. A method for addressing a central memory for interrogation thereof and retrieval of data stored therein, said addressing taking place in dependence on the operational states of a system which is itself controlled by the data in said central memory, at least one of said operational states being dependent on another state, preferably the temperature of the system, and in particular adapted to controlling an electronic fuel injection system for generating a correction frequency by using the data retrieved from said central memory, for processing by a main processor and for generation of injection pulses to control the opening times of fuel injection valves of the engine, the improvement comprising:
deriving switching signals from prevailing operational states of the system and feeding said switching signals to a decoder circuit, cyclically activating said decoder for generating a single pre-address selector signal corresponding to each combination of operational states, said pre-address selector signal being fed to an address memory for generating a digital address, a first part of which is fed directly to said main processor for selecting an address range and a second portion of which being fed to a counter which is thereby set to an initial value, gating said counter for a predetermined length of time, feeding to said counter a clock pulse train dependent on said operational state of the system, thereby causing said counter to count upwardly from its initial value, and delivering the final contents of said counter at the expiration of said gating time to said central memory for providing the complete address therein, and closing the gating input to said counter if a particular combination of operational states is independent of said other operational state.
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2. In an apparatus for addressing a central memory for interrogation thereof and retrieval of data stored therein, said addressing taking place in dependence on the operational states of a system which is itself controlled by the data in said central memory, at least one of said operational states being dependent on another state, preferably the temperature of the system, and in particular adapted to controlling an electronic fuel injection system for generating a correction frequency by using the data retrieved from said central memory, for processing by a main processor and for generation of injection pulses to control the opening times of fuel injection valves of the engine, the improvement comprising:
means for sensing operational states of the controlled system, means for generating switching signals from said sensed states, decoder means for receiving said switching signals and for generating a plurality of single signals activated in cyclic manner for delivery to an address memory containing address data, the output of said address memory being divided into a first portion and a second portion, said first portion being fed to a central memory and said second portion being fed to a counter for initialization of the contents thereof, means for generating a temperature-dependent frequency and gating means for admitting said temperature-dependent frequency to said counter for continuous counting from said initialized count;
whereby, when the gating means have terminated the gating process, said counter contains a number for delivery to said central memory to form together with said first portion an address for delivery of a datum associated therewith in said central memory.- View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
Specification