| 摘要 |
A point of sale terminal includes a microcontroller integrated circuit. In one aspect, a regulator within the IC receives power from a supply voltage terminal and/or a battery terminal. If the regulator does not receive adequate power from either terminal, then energy stored on-chip in a capacitor is used to erase secure memory. In another aspect, pulses of current are made to pulse through conductors of a conductive mesh. A tamper condition is detected if an improper voltage is detected on the IC terminal through which the pulse is conducted. In another aspect, each vendor signs his/her firmware with his own vendor ID. A bootloader uses the vendor ID to lookup a public key that is then used to verify a private key supplied by the firmware to be executed. In another aspect, a magnetic card reader includes a digital peak detector circuit involving programmable positive and negative thresholds.
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