Echelon I/O Model Reference for Smart Transceivers and Neuron Chips - Manual (Page 17)

I/O Model Reference 7
I/O Model Applicable I/O Pins Total Pins
per Object
Input/Output Value Page
Pulsewidth Output IO0, IO1 1 0 – 100% duty cycle pulse
train
171
Stretched Triac
Output 1
IO0, IO1 + (one of
IO4 – IO7)
2 Delay of output pulse with
respect to input edge
174
Triac Output 2 IO0, IO1 + (one of
IO4 – IO7) 2 Delay of output pulse with
respect to input edge 179
Triggered-
Count Output IO0, IO1 + (one of
IO4 – IO7) 2 Output pulse controlled by
counting input edges 183
Notes:
1. The Stretched Triac Output model is available only for the following device types: FT
5000 and Neuron 5000.
2. Dual-edge triggering is not available for the following device types: Neuron 3150, FT
3150, or PL 3150.
See Chapter 6, Timer/Counter Output Models , on page 155, for more information
about the timer/counter output models.
Neuron Chips and Smart Transceivers have two 16-bit timer/counters on-chip.
The input to timer/counter 1, also called the
multiplexed timer/counter, is
selectable among pins IO4 – IO7, through a programmable multiplexer and its
output can be connected to pin IO0. The input to timer/counter 2, also called the
dedicated timer/counter, can be connected to pin IO4 and its output to pin IO1.
The timer/counters are implemented as a 16-bit load register writable by the
CPU, a 16-bit counter, and a 16-bit latch readable by the CPU. The load register
and latch are accessed a byte at a time. No I/O pins are dedicated to
timer/counter functions. If, for example, timer/counter 1 is used for input signals
only, then IO0 is available for other input or output functions. Timer/counter
clock and enable inputs can be from external pins, or from scaled clocks derived
from the system clock; the clock rates of the two timer/counters are independent
of each other. External clock actions occur optionally on the rising edge, the
falling edge, or both rising and falling edges of the input.
For Series 5000 devices, many of the timer/counter I/O models can also trigger
interrupt tasks, which can provide minimum application latency for I/O events
that are related to the timer/counter models. See the Neuron C Programmer’s
Guide for more information about defining and using interrupts for Series 5000
devices.
Multiple timer/counter input objects can be declared on different pins within a
single application. By calling the io_select()
function, the application can use the
first timer/counter to implement up to four different input objects. If a
timer/counter is configured to implement one of the output models, or is
configured as a quadrature input object, then it can not be reassigned to another
timer/counter object in the same application program.