Echelon FT 3150 Smart Transceiver - Manual (Page 95)

FT 3120 / FT 3150 Smart Transceiver Data Book 89
Notes
The gradient behavior of the timing numbers for different FT Smart Transceiver pins for some of the I/O objects is
due to the shift-and-mask operation performed by the Neuron firmware.
For dualslope input, edgelog input, ontime input, and period input, the timer/counter returns a value (or a table of
values, in the case of edgelog input) in the range 0 to 65,535, representing elapsed times from 0 up to the maximum
range given in Table 3.6.
For ontime input, period input, dualslope, edgelog, and infrared; the timer/counter returns a number in the range 0 to
65,535, representing elapsed times from 0 up to the maximum range given in Table 3.6.
For oneshot output, frequency output, and triac output; the timer/counter may be programmed with a number in the
range 0 to 65,535. This number represents the waveform ontime for oneshot output, the waveform period for
frequency output, and the control period from sync input to pulse/level output for the triac output. Table 3.6 gives the
range and resolution for these timer/counter objects at 10MHz. The clock select value is specified in the declaration
of the I/O object in the Neuron C application program, and may be modified at runtime.
Table 3.6 Timer/Counter Resolution and Maximum Range
This table is for a 10MHz input clock. Scale appropriately for other clock rates:
Resolution (µs) = 2 (Clock Select + n) /(Input Clock in MHz)
Maximum Range (µs) = 65535 x Resolution (µs) x n
n = 1 for oneshot and triac output, and dualslope, edgelog, ontime, and period input
n = 2 for frequency output.
For 20MHz operation, the numbers in this table would be half the value shown.
For pulsewidth short output and pulsecount output, Table 3.7 gives the possible choices for pulsetrain repetition
frequencies. Pulsecount can not be used with clock select 0.
Clock Select
Oneshot and Triac Outputs;
Dualslope, Edgelog, Ontime,
and Period Inputs
Frequency Output
Resolution
(µs)
Maximum
Range
(ms)
Resolution
(µs)
Maximum
Range
(ms)
0 0.2 13.1 0.4 26.2
1 0.4 26.2 0.8 52.4
2 0.8 52.4 1.6 105
3 1.6 105 3.2 210
4 3.2 210 6.4 419
5 6.4 419 12.8 838
6 12.8 839 25.6 1,678
7 25.6 1,678 51.2 3,355