Method for transferring data between devices by generating a strobe pulse and clamping a clock line
First Claim
1. A method of transferring data between a first device and a second device intercoupled by a data line and a clock line, the method comprising the steps of:
- A. controlling the first device to generate a clock signal on the clock line, the clock signal oscillating between an active state and an inactive state;
B. controlling the first device in response to the clock signal generated in step A to sequentially generate a plurality of data bits on the data line, each of the data bits comprising a data signal which has at least two logic levels and changes between the logic levels only when the clock signal is in the inactive state;
C. controlling the first device to generate a strobe pulse signal on the data line after the plurality of data bits have been generated, the strobe pulse signal changing from a first logic value to a second logic value and back to the first logic value while the clock signal is maintained constant in the active state;
D. receiving the plurality of data bits, the clock signal and the strobe signal in the second device;
E. controlling the second device to perform an operation upon the plurality of data bits in response to the reception of the strobe signal in step D;
F. controlling the second device to clamp the clock line to a predetermined logic value during step E; and
G. controlling the first device to monitor the clock line, the first device refraining from generating data bits on the data line while the clock line is clamped to the predetermined logic value.
5 Assignments
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Accused Products
Abstract
A first and second electronic devices are connected by two data lines arranged in a wired-AND configuration so that each device can signal the other device by forcing one of the two-wires into a "low" condition. An inventive method uses serial transfer of a predetermined numbers of bits in a digital word delimited by start and stop bits which are, in turn, defined by their relation to a clock signal on one of the data lines. The start and stop bits are chosen to be in a particular state during the "active" portion of the clock signal. Thus, the need for clocked gates or multivibrators is eliminated. In the preferred embodiment, the method and apparatus are used in a digital multimeter to intercouple a microprocessor and an electronic measuring circuit so that the microprocessor can control the measuring circuit and receive measured values from the circuit.
26 Citations
6 Claims
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1. A method of transferring data between a first device and a second device intercoupled by a data line and a clock line, the method comprising the steps of:
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A. controlling the first device to generate a clock signal on the clock line, the clock signal oscillating between an active state and an inactive state; B. controlling the first device in response to the clock signal generated in step A to sequentially generate a plurality of data bits on the data line, each of the data bits comprising a data signal which has at least two logic levels and changes between the logic levels only when the clock signal is in the inactive state; C. controlling the first device to generate a strobe pulse signal on the data line after the plurality of data bits have been generated, the strobe pulse signal changing from a first logic value to a second logic value and back to the first logic value while the clock signal is maintained constant in the active state; D. receiving the plurality of data bits, the clock signal and the strobe signal in the second device; E. controlling the second device to perform an operation upon the plurality of data bits in response to the reception of the strobe signal in step D; F. controlling the second device to clamp the clock line to a predetermined logic value during step E; and G. controlling the first device to monitor the clock line, the first device refraining from generating data bits on the data line while the clock line is clamped to the predetermined logic value. - View Dependent Claims (2)
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3. A method of transferring data between a first device and a second device intercoupled by a data line and a clock line, the method comprising the steps of:
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A. controlling the first device to generate a clock signal on the clock line, the clock signal oscillating between an active state and an inactive state; B. controlling the first device in response to the clock signal generated in step A to sequentially generate a plurality of data bits on the data line, each of the data bits comprising a data signal which has at least two logic levels and changes between the logic levels only when the clock signal is in the inactive state; C. controlling the first device to generate a strobe pulse signal on the data line after the plurality of data bits have been generated, the strobe pulse signal changing from a first logic value to a second logic value and back to the first logic value while the clock signal is maintained constant in the active state; D. receiving the plurality of data bits, the clock signal and the strobe 18 signal in the second device; E. controlling the second device to perform an operation upon the plurality of data bits in response to the reception of the strobe signal in step D; F1. controlling the second device to monitor a predetermined one of the plurality of data bits received in step D; F2. controlling the second device to clamp the clock line to a first predetermined logic value during step E when the predetermined one of the plurality of data bits received in step D has a second predetermined logic value; and G. controlling the first device to monitor the clock line, the first device refraining from generating data bits on the data line while the clock line is clamped to the first predetermined logic value.
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4. A method of transferring data between a first device and a second device intercoupled by a data line and a clock line, the method comprising the steps of:
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A. controlling the first device to generate a clock signal on the clock line, the clock signal oscillating between an active state and an inactive state; B. controlling the first device in response to the clock signal generated in step A to sequentially generate a plurality of data bits on the data line, each of the data bits comprising a data signal which has at least two logic levels and changes between the logic levels only when the clock signal is in the inactive state; C. controlling the first device to generate a strobe pulse signal on the data line after the plurality of data bits have been generated, the strobe pulse signal changing from a first logic value to a second logic value and back to the first logic value while the clock signal is maintained constant in the active state; D. receiving the plurality of data bits, the clock signal and the strobe signal in the second device; E. controlling the second device to perform an operation upon the plurality of data bits in response to the reception of the strobe signal in step D; F. controlling the second device to clamp the clock line to a predetermined logic value during step E; G. controlling the first device to monitor the clock line, the first device refraining from generating data bits on the data line while the clock line is clamped to the predetermined logic value; H. controlling the second device to release the clock line at the completion of step E; I. controlling the first device to generate a strobe pulse signal on the data line at the completion of step H; and J. controlling the second device in response to the strobe pulse signal generated in step I to sequentially generate a plurality of data bits on the data line, each of the data bits comprising a data signal which has at least two logic levels. - View Dependent Claims (5)
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6. A method of transferring data between a first device and a second device intercoupled by a data line and a clock line, the method comprising the steps of:
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A. controlling the first device to generate a clock signal on the clock line, the clock signal oscillating between an active state and an inactive state; B. controlling the first device in response to the clock signal generated in step A to sequentially generate a plurality of data bits on the data line, each of the data bits comprising a data signal which has at least two logic levels and changes between the logic levels only when the clock signal is in the inactive state; C. controlling the first device to generate a strobe pulse signal on the data line after the plurality of data bits have been generated, the strobe pulse signal changing from a first logic value to a second logic value and back to the first logic value while the clock signal is maintained constant in the active state; D. receiving the plurality of data bits, the clock signal and the strobe signal in the second device; E. controlling the second device to perform an operation upon the plurality of data bits in response to the reception of the strobe signal in step D; F. controlling the first device to generate a reset pulse signal on the data line, the reset pulse signal changing from the second logic value to the first logic value and back to the second logic value while the clock signal is in the active state; G. receiving the reset pulse signal at the second device; and H. placing the second device in a predetermined state in response to the reception of the reset signal in step G.
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Specification