Remote keyless entry rolling code storage method
First Claim
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1. A system comprising first and second modules, wherein said first module comprises:
- a first memory in said second module for initially storing a first code; and
a transmitter for transmitting a current transmission from said first module to said second module, the transmission including a first sync code, and said second module comprising;
a second memory initially providing a plurality of sync memory areas, each of said sync memory areas being adapted to store a sync code and a copy of the first code;
a receiver for receiving the current transmission from said first module;
identifying means for identifying a first one of said sync memory areas as storing a copy of the first code and a second sync code received from said first module in a first previous transmission;
first determining means for determining whether or not the second sync code is usable by determining whether the first code stored in said first memory corresponds to the copy of the first code stored in said first sync memory area;
second determining means for, if the second sync code is determined to be usable, determining whether or not said first and second modules are in synchronization based on the first sync code received in the current transmission and the second sync code stored in said first sync memory area, wherein, if the second sync code is determined not to be usable, said identifying means identifies a second one of said sync memory areas as storing a third sync code received from said first module in a second previous transmission, and determining whether or not said first and second modules are in synchronization based on the first sync code received in the current transmission and the third sync code stored in said second sync memory area; and
writing means for, if said first and second modules are determined to be in synchronization, writing the first sync code and another copy of the first code from said first memory in a selected one of said sync memory areas.
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Abstract
A remote keyless entry system stores critical data for synchronization in a plurality of memory locations at the receiver. When a transmission is received, the received data is validated using the critical data from a first memory location. In the event that the data in the first memory location is determined to be unusable, the critical data from a second memory location is used. The critical data is rewritten at the first memory location only if the transmission is ultimately determined to be valid.
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Citations
20 Claims
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1. A system comprising first and second modules, wherein said first module comprises:
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a first memory in said second module for initially storing a first code; and
a transmitter for transmitting a current transmission from said first module to said second module, the transmission including a first sync code, and said second module comprising;
a second memory initially providing a plurality of sync memory areas, each of said sync memory areas being adapted to store a sync code and a copy of the first code;
a receiver for receiving the current transmission from said first module;
identifying means for identifying a first one of said sync memory areas as storing a copy of the first code and a second sync code received from said first module in a first previous transmission;
first determining means for determining whether or not the second sync code is usable by determining whether the first code stored in said first memory corresponds to the copy of the first code stored in said first sync memory area;
second determining means for, if the second sync code is determined to be usable, determining whether or not said first and second modules are in synchronization based on the first sync code received in the current transmission and the second sync code stored in said first sync memory area, wherein, if the second sync code is determined not to be usable, said identifying means identifies a second one of said sync memory areas as storing a third sync code received from said first module in a second previous transmission, and determining whether or not said first and second modules are in synchronization based on the first sync code received in the current transmission and the third sync code stored in said second sync memory area; and
writing means for, if said first and second modules are determined to be in synchronization, writing the first sync code and another copy of the first code from said first memory in a selected one of said sync memory areas. - View Dependent Claims (2)
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3. A method for validating synchronization between a first module and a second module, comprising the steps of:
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initially storing a first code in a first memory area in the second module;
initially providing a plurality of sync memory areas, other than the first memory area, in the second module, each of the sync memory areas being adapted to store a sync code and a copy of the first code; and
transmitting a current transmission from the first module to the second module, the transmission including a first sync code, said method further comprising the steps, in the second module, of;
receiving the current transmission from the first module;
identifying a first one of the sync memory areas as storing a copy of the first code and a second sync code received from the first module in a first previous transmission;
determining whether or not the second sync code is usable by determining whether the first code stored in the first memory area corresponds to the copy of the first code stored in the first sync memory area;
if the second sync code is determined to be usable, determining whether or not the first and second modules are in synchronization based on the first sync code received in the current transmission and the second sync code stored in the first sync memory area;
if the second sync code is determined not to be usable, identifying a second one of the sync memory areas as storing a third sync code received from the first module in a second previous transmission, and determining whether or not the first and second modules are in synchronization based on the first sync code received in the current transmission and the third sync code stored in the second sync memory area; and
if the first and second modules are determined to be in synchronization, writing the first sync code and another copy of the first code in a selected one of the sync memory areas. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
determining whether or not a received transmission is from one of the mated first modules by determining whether an identifier code in the received transmission matches one of the identifier codes stored in the second module; and
terminating said method if there is no match.
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10. The method of claim 9, wherein the second module stores a respective plurality of sync memory areas for each first module, and said method identifies a corresponding one of the pluralities of sync memory areas based upon a match between the identifier code in the received transmission and one of the stored identifier codes.
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11. The method of claim 3, wherein the sync memory area selected to be written into is a sync memory area following the first sync memory area.
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12. A method for validating synchronization between a fob and a control module of a vehicle to authorize commands sent from the fob to the control module, said method comprising the steps of:
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initially storing a master key code in a master key code area of the control module;
initially providing a plurality of sync memory areas, other than the master key code area, in the control module, each of the sync memory areas being adapted to store a sync code and a copy of the master key code; and
transmitting a current transmission from the fob to the control module, the transmission including a first sync code, said method further comprising the steps, in the control module, of;
receiving the current transmission from the fob;
identifying a first one of the sync memory areas as storing a copy of the master key code and a second sync code received from the fob in a first previous transmission;
determining whether or not the second sync code is usable by determining whether the master key code stored in the master key code area corresponds to the copy of the master key code stored in the first sync memory area;
if the second sync code is determined to be usable, determining whether or not the fob and the control module are in synchronization based on the first sync code received in the current transmission and the second sync code stored in the first sync memory area;
if the second sync code is determined not to be usable, identifying a second one of the sync memory areas as storing a third sync code received from the fob in a second previous transmission, and determining whether or not the fob and the control module are in synchronization based on the first sync code received in the current transmission and the third sync code stored in the second sync memory area; and
if the fob and the control module are determined to be in synchronization, writing the first sync code and another copy of the master key code from the master key code area in a selected one of the sync memory areas. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
determining whether or not a received transmission is from one of the mated fobs by determining whether an identifier code in the received transmission matches one of the identifier codes stored in the control module; and
terminating said method if there is no match.
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19. The method of claim 18, wherein the control module stores a respective plurality of sync memory areas for each fob, and said method identifies a corresponding one of the pluralities of sync memory areas based upon a match between the identifier code in the received transmission and one of the stored identifier codes.
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20. The method of claim 12, wherein the sync memory area selected to be written into is a sync memory area following the first sync memory area.
Specification