公开(公告)号：EP1607899B1

公开(公告)日：2007-08-15

申请号：EP04253573.2

申请日：2004-06-15

Applicant: STMicroelectronics Limited

Inventor： Whaley, Jeremy ,  Hutson, Matthew

IPC: G06K7/00 ,  G06K13/08

CPC classification number: G06K7/0069 ,  G06K7/0021

公开(公告)号：EP1607899A1

公开(公告)日：2005-12-21

申请号：EP04253573.2

申请日：2004-06-15

Applicant: STMicroelectronics Limited

Inventor： Whaley, Jeremy ,  Hutson, Matthew

IPC: G06K7/00 ,  G06K13/08

CPC classification number: G06K7/0069 ,  G06K7/0021

Abstract: An embodiment of the invention comprises a card reader for reading data stored on a card. A contact signal is produced whose state is indicative of the presence or absence of electrical contact between the card and the card reader. A high state indicates the presence of electrical contact and a low state indicates the absence of electrical contact. Upon insertion of the card into the card reader, vibrations and other mechanical perturbations of the card cause the state of the contact signal to fluctuate rapidly between high and low states. The state of the contact signal is periodically sampled for a predetermined period of time and the number of samples for which the contact signal was high are counted. If the number of high samples exceeds a threshold then stable electrical contact is deemed to have been established between the card and the card reader and a system reset is performed. In one embodiment, the contact signal is sampled once every millisecond for 64 milliseconds, and a system reset occurs if the number of high samples exceeds 47.

Abstract translation: 本发明的实施例包括用于读取存储在卡上的数据的读卡器。 产生接触信号，其状态指示卡和读卡器之间是否存在电接触。 高电平表示存在电接触，低电位表示不存在电接触。 当将卡插入读卡器时，卡的振动和其他机械扰动导致接触信号的状态在高状态和低状态之间迅速波动。 接触信号的状态在预定的时间周期内被周期性地采样，并对接触信号为高的样本数进行计数。 如果高采样数超过阈值，则认为在卡和读卡器之间建立了稳定的电接触，并执行系统复位。 在一个实施例中，接触信号每毫秒采样一次，持续64毫秒，如果高采样数超过47，则发生系统复位。