Echelon FT 3150 Smart Transceiver - Manual (Page 78)

Chapter 3 - Input/Output Interfaces
72 FT 3120 / FT 3150 Smart Transceiver Data Book
The resolution and range of the timer/counter period options is shown by Table 3.6 in section , Notes, at the end of
this chapter.
Figure 3.36 Dualslope Input Object
Edgelog Input
The edgelog input object can record a stream of input pulses measuring the consecutive low and high periods at the
input and storing them in user-defined storage (see Figure 3.37). The values stored represent the units of clock period
between rising and falling input signal edges. Both timer/counters of the FT Smart Transceiver are used for this
object.
The measurement series starts on the first rising (positive) edge, unless the invert keyword is used in the I/O object
declaration. The measurement process stops whenever an overflow condition is sensed on either timer/counter.
Symbol Description Min Typ Max
t
reqo
io_in_request() to output toggle — 75.6 µs —
t
fin
Input function call and return — 82.8 µs —
Timer/Counter 1
Timer/Counter 2
IO10
IO9
IO8
IO0
IO1
IO2
IO3
IO4
IO5
IO6
IO7
mux
Control Output
From
Comparator
OUTPUT
(IO0 OR IO1)
START OF
io_in_request()
END OF
io_in() LATCHED COUNT
AVAILABLE TO
APPLICATION
START
OF io_in()
TIME
INPUT
(IO4 TO IO7)
t
fin
ANALOG SWITCH
CONTROL
COMPARATOR
OUTPUT
INTEGRATOR
OUTPUT
V
thresh
t
reqo