HCTL-2000 Datasheet, PDF (13/18 Pages) Agilent(Hewlett-Packard) – Quadrature Decoder/Counter Interface ICs

Actions
1. On the rising edge of the clock,
counter data is transferred to
the position data latch,
provided the inhibit signal is
low.
2. When OE goes low, the
outputs of the multiplexer are
enabled onto the data lines. If
SEL is low, then the high order
data bytes are enabled onto the
data lines. If SEL is high, then
the low order data bytes are
enabled onto the data lines.
3. When the IC detects a low on
OE and SEL during a falling
clock edge, the internal inhibit
signal is activated. This blocks
new data from being
transferred from the counter to
the position data latch.
4. When SEL goes high, the data
outputs change from the high
byte to the low byte.
5. The first of two reset condi-
tions for the inhibit logic is
met when the IC detects a
logic high on SEL and a logic
low on OE during a falling
clock edge.
6. When OE goes high, the data
lines change to a high imped-
ance state.
7. The IC detects a logic high on
OE during a falling clock edge.
This satisfies the second reset
condition for the inhibit logic.
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