Gregory's ServerI dissolved the chip's metal and oxide layers to reveal the chip's underlying silicon, showing the layout of its transistors. 7/15
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5 comments
 Most of the chip is digital logic, implemented with standard-cell circuitry, but there's lots of analog circuitry to handle the antenna signal. The four bond pads are where the antenna is attached. 9/15 Many chips use standard-cell circuitry. A program converts the logic description into rows of standardized blocks (NAND gates, flip-flops, etc.) and lays out the metal wiring between them. Much faster than creating an optimized layout by hand. 10/15  @kenshirriff Does this mean that the back-end has a database of all issued tickets (identified by their UID), and whether they have been tapped in and/or out? |
This block diagram from the datasheet shows the components of the card. The RF interface is the analog circuitry connected to the antenna. The card stores 48 bytes (the ticket info) in the EEPROM. The digital circuitry accepts commands to read and write the EEPROM. 8/15