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Encoder Divider Introduction
Version G.5 BitFlow, Inc. NEO-5-1
Encoder Divider
Chapter 5
5.1 Introduction
This section covers the encoder divider which supported on the Karbon and the Neon
Families. The purpose of Encoder Divider is to provide the ability to use an encoder
running at one rate to drive a line scan camera at a different rate. This circuit is only
useful for line scan cameras. The Encoder Divider can scale up or down the incoming
encoder frequency. The encoder divider is fully programmable and is easily con-
trolled from software and/or from camera configuration files.
The factor used to scaled the incoming encoder frequency does not have to be a
whole number. For example, the encoder could be scaled by 0.03448 or 4.2666). Of
course not all ration numbers in the available scaling range can be selected (there are
an infinite number of them). However, a useful selection of values is available which
should support most applications.
The Encoder Divider circuit takes as its input the selected encoder input (controlled
by the register SELENC). The output of the encoder divider drives the same parts of
the board the normal encoder usually does. The actual circuit(s) being driven
depends on how the board is programmed. However, the Encoder Divider circuit can
drive any of the following:
Horizontal CTAB (HCNT_RLS_ZERO = 1)
NTG (NTG_ONESHOT = 1, NTG_TRIG_MODE = 1)
Note: The Encoder Divider circuit described in this chapter replaces the previous
circuit which could only divide the incoming encoder by an integer value and could
not increase the encoder frequncy. Please contact BitFlow if you have been using the
previous on-board encoder divider.