Rechargeable prepaid memory card with both unit and page counters
First Claim
1. An electronic memory card for counting units, said memory card being adapted to count up to a total of N×
- P units, where N and P are integers, comprisinga memory zone with an array of P electrically programmable memory cells each of which has two possible states which are respectively a non-programmed state and a programmed state, wherein a programming step of one memory cell from the non-programmed state to the programmed state represents a counting of one unit;
means for successively programming the P cells;
a page counter for counting groups of P units, each group of P units being referred to as a page of units;
an incrementation circuit for incrementing the page counter by one unit when all the P cells have been successively programmed;
erasing means for re-setting the P cells to said non-programmed state after they have been successively programmed;
a credit counter, having a maximum count to a variable integer Z which at most is equal to N, and wherein Z represents an available credit proportional to units and a number of pages of P units;
a comparator connected to the page counter and the credit counter for comparing the contents of said counters and for emitting a no-more-credit signal when the content of the page counter corresponds to Z; and
the credit counter having a connection means for it to be incremented from outside the memory card.
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Accused Products
Abstract
The disclosure concerns memory cards and, more particularly, cards that are used as means of prepayment in installations for the dispensing of products and services. It is proposed to make the memory rechargeable by means of a credit counter, incrementable from outside the card, and a comparator which compares the content of this counter with that of a page counter. The page counter records the number of pages of P accounting units already used up. A no more credit signal is emitted on an external terminal when the content of the page counter reaches the content of the credit counter. A security system against the fraudulent recharging of the card is set up by an algorithm bringing into play the content of the credit counter and an identification number contained in the card.
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Citations
5 Claims
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1. An electronic memory card for counting units, said memory card being adapted to count up to a total of N×
- P units, where N and P are integers, comprising
a memory zone with an array of P electrically programmable memory cells each of which has two possible states which are respectively a non-programmed state and a programmed state, wherein a programming step of one memory cell from the non-programmed state to the programmed state represents a counting of one unit; means for successively programming the P cells; a page counter for counting groups of P units, each group of P units being referred to as a page of units; an incrementation circuit for incrementing the page counter by one unit when all the P cells have been successively programmed; erasing means for re-setting the P cells to said non-programmed state after they have been successively programmed; a credit counter, having a maximum count to a variable integer Z which at most is equal to N, and wherein Z represents an available credit proportional to units and a number of pages of P units; a comparator connected to the page counter and the credit counter for comparing the contents of said counters and for emitting a no-more-credit signal when the content of the page counter corresponds to Z; and the credit counter having a connection means for it to be incremented from outside the memory card. - View Dependent Claims (2, 3, 4, 5)
- P units, where N and P are integers, comprising
Specification