Echelon I/O Model Reference for Smart Transceivers and Neuron Chips - Manual (Page 140)

130 Timer/Counter Input Models
For a Series 5000 device, this I/O model measures a series of both high and low
input signal periods on a single input pin, IO_4, in units of the clock period:
time_on/time_off (ns) = value_stored * 2000 * 2^(value) / 10 MHz
where value ranges from 0..15
Edgelog input can be used to capture complex waveforms such as infrared
command input (see also
Infrared Input on page 134), or to decode any type of
bitstream that contains data in the time domain (an arbitrarily-spaced stream of
input edges or pulses), such as bar code input.
This model applies to Series 3100 Neuron Chips and Smart Transceivers, and to
Series 5000 Neuron Processors and Smart Transceivers.
Hardware Considerations
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.
The resolution and range of the timer/counter period options is described in
Timer/Counter Resolution and Maximum Range on page 188.
Timer/Counter 1
Timer/Counter 2
IO10
IO9
IO8
IO0
IO1
IO2
IO3
IO4
IO5
IO6
IO7
Input
Bit Stream
IO11
END
OF io_in()
OVERFLOW
TIME
INPUT
(IO4)
START OF
io_in()
t
win
t
wtcp
t
ret
t
oret
t
hold
t
setup
Figure 49. Edgelog Input and Timing