beautypg.com

Programming considerations, Syntax – Echelon I/O Model Reference for Smart Transceivers and Neuron Chips User Manual

Page 195

background image

I/O Model Reference

185

Table 65. Triggered Count Output Latency Values for Series 3100 Devices

Symbol

Description

Typical at 10 MHz

t

fout

Function call to output update

109 μs

t

cod

Last negative sync
Clock edge to output inactive

min 550 ns
max 750 ns

t

ret

Return from function

7 μs

Programming Considerations

The triggeredcount I/O model is used to control an output pin to the active state

and keep it active until

output-value

negative edges are counted at the input sync

pin. After

output-value

edges have counted off, the output pin returns to the low

state.
For triggeredcount output, the data type of

output-value

for the io_out( ) function

is an unsigned long. An

output-value

of 0 forces the output signal to an inactive

state.

Syntax

pin

[output] triggeredcount sync (

pin-nbr

) [invert]

io-object-name

[=

initial-output-level

] ;


pin

An I/O pin. Triggeredcount output can specify pins IO_0 or IO_1. If IO_0 is

specified, the multiplexed timer/counter is used and the sync pin can be IO_4

through IO_7. If IO_1 is specified, the dedicated timer/counter is used and
the sync pin must be IO_4.

sync (

pin-nbr

)

Specifies the sync pin, which is the counting input signal with low pulses.

invert

Causes the output signal to be inverted, normally high. By default, the
output signal is normally low with high pulses.

io-object-name

A user-specified name for the I/O object, in the ANSI C format for variable
identifiers.

initial-output-level

A constant expression, in ANSI C format for initializers, used to set the state
of the output pin of the I/O object at initialization. The initial state can be 0

or 1. The default initial state is 0.