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TIDE and Tibbo BASIC User Manual
©2000-2008 Tibbo Technology Inc.
The CTS line is not controlled by the serial port when in the half-duplex mode.
Your application can manipulate this line through the
object.
Wiegand Mode
In the Wiegand mode the serial port is able to receive the data directly from any
Wiegand device, such as card reader and also output the data in the Wiegand
format, as if it was a card reader itself. Wiegand interface is popular in the
security, access control, and automation industry.
Standard Wiegand data transmission is shown below. There are two data lines- W0
and W1. Negative pulse on the W0 line represents data bit 0. Negative pulse on
the W1 line represents data bit 1. There is no standard Wiegand timing, so pulse
widths as well as inter-gap widths wary greatly between devices. Averagely, pulse
width is usually in the vicinity of 100uS (microseconds), while the inter-pulse gap
is usually around 20-100ms (milliseconds).
There is no explicit way to indicate the end of transmission. Receiving device either
counts received bits (if it knows how many to expect) or assumes the transmission
to be over when the time since the last pulse on the W0 or W1 line exceeds certain
threshold, for example, ten times the expected inter-pulse gap.
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