EMPROT Datasheet, PDF (5/17 Pages) rfsolutions.ltd – Micro RWD EM4102 Low Power Version

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THE RWD HAS THREE POLLING STATES:
1) NO card present and NO host commands received.
Polling cycle rate (time between subsequent CTS low periods) is determined by the
“polling rate” parameter stored in the RWD EEPROM memory. This is typically set
to a long period (0 to 8 seconds, default setting 260mS) and is the primary means to
reduce average power consumption. This is because most of the polling cycle period is
spent in a power-down/sleep mode.
Not to scale
CTS
TTL levels
5v
6ms
(CTS timeout)
Polling cycle period set by RWD EEPROM
parameter (4ms to 8 seconds, default 1 second)
0v
Polling cycle
repeats
RF OFF, Power-down/sleep period
RF ON for brief period
(to check for card)
2) EM4102 card in field, NO host commands received.
When a card is detected in the field the polling rate changes to approximately 100ms
(between CTS low periods). This is to ensure that the RWD can respond quickly to the
card leaving the field and a new card being presented.
Not to scale
CTS
100ms polling rate
6ms (CTS timeout)
100ms polling rate
TTL levels
5v
0v
Polling cycle
repeats
RF OFF, Power-down/sleep period RF ON for brief period (to check for card)
3) Host commands received and processed.
When the RWD receives commands from the host computer, the polling rate increases
to allow a quick response to the command. This means that commands such as READ
TAG can be repeated quickly with no polling delay (sleep period) between cycles.
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