Echelon I/O Model Reference for Smart Transceivers and Neu Manual de usuario descargar pdf (Pagina 52)

42 Direct I/O Models

Figure 16. Nibble Output Timing

Table 17. Nibble Output Latency Values for Series 3100 Devices

Symbol Description Typical at 10 MHz

fout

Function call to update

IO0

IO1

IO2

IO3

IO4

78 μs

89.8 μs

101.5 μs

113.5 μs

125 μs

ret

Return from function

IO0 – IO4

5 μs

Programming Considerations

For nibble input/output, the data type of

return_value

for the io_in( ) function,

and the data type of the output value for the io_out( ) function is an unsigned

short.

For Series 3100 devices, add a #pragma enable_io_pullups directive to enable the

Neuron Chip’s or Smart Transceiver's built-in pull-up resistors on pins IO_4

through IO_7.

Syntax

input nibble

io-object-name

;

output nibble

io-object-nam

e [=

initial-output-level

];

An I/O pin. Nibble input/output requires four adjacent pins. The pin

specification denotes the lowest numbered pin of the set and can be IO_0

1 2 ... 47 48 49 50 51 52 53 54 55 56 57 ... 208 209

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Echelon I/O Model Reference for Smart Transceivers and Neu Manual de usuario Pagina 52