MagTek SWIPE READERS WITH 3-TRACK - Manual (Page 12)

Swipe Readers With 3-Track SPI IntelliHead
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Two SPI modes are supported by this reader, Mode A (CPHA=1, CPOL=1) and Mode D
(CPHA=0, CPOL=0). Mode A means that the SCL clock line idles in a high state prior to DAV
assertion. For Mode D, SCL idles low. Otherwise, data is collected by the Host in the same
manner, either on the rising edge of SCL or while SCL is high.
The SPI Bus Interface Timing is shown in Figure 3-1.