Bitronics QTWIE2, Руководство пользователя

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ML0030 August 2009 Copyright 2009 Bitronics, LLC
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2.7 LED Display Board (LED Board)
The LED Display board consists of two 3 1/2 digit displays (one in the case of the WTWIE3
or RTWIE3), comprised of high efficiency red LED seven segment common cathode
displays. Each 3 1/2 digit display is driven in a multiplexed fashion by an MC14499 seven
segment decoder driver chip, which accept serial data from the MCU, and decodes the
data into the seven segment and digit select outputs necessary for the multiplexed display.
The high current cathode drive is provided by an MC1472 driver for each pair of digits. On
power up or any other time the MCU is reset, a display test will be conducted that displays
+1.8.8.8 on the top display, followed by +1.8.8.8 on the bottom display (QTWIE2 only).
The display test can be initiated by entering and then leaving the CT/PT set mode (see
section 4.1).