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2.11.2 Communication functions
Reading and writing of IC card data is performed by way of contactless communication between
an NFC module and an IC card. IC cards are preprogrammed to perform certain operations in
response to prescribed commands. When a command is correctly transmitted to an IC card, the
card responds to the received command by performing a corresponding operation. Once the
operation is complete, the card then transmits response information indicating the result of the
operation.
An explanation of the functions relating to this communication process is provided below.
Card polling function
1. Search for IC cards within the communicable range
2. IC card detection
3. IC card activation
4. Acquisition of IC card response information
The card polling function terminates the search for IC cards when: it detects a smart card; the
timeout elapses; the assigned callback function returns a 'FALSE' value; or the 'stop polling'
function is executed.
Once the IC card has been successfully activated, the NFC module continually transmits radio
waves in order to supply power to the smart card. This radio wave transmission terminates
automatically when the 'radio off' function is executed or when a certain time elapses without any
data communication between the NFC module and the IC card. It is possible to enable or disable
the automatic stop (auto stop) setting and to change the time until the auto stop occurs (i.e. the
timeout). Under the default settings, auto stop is enabled and the timeout is set at 1,000
milliseconds.
* If there are multiple IC cards within the communicable range, it is not possible to start just one
of them, or all of them. It is necessary to bring each IC card into proximity one card at a time in
order to ensure proper communication.
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