Digi NS9750 Uživatelský manuál stáhnout pdf (Strana 77)

IEEE 1284 timing

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IEEE 1284 timing

IEEE 1284 AC characteristics are measured with 10pF, unless otherwise noted.

Table 35 describes the values shown in the IEEE 1284 timing diagram.

Notes:

1 The range is 0ns up to one time unit.

2 Two time units.

3 Three time units.

IEEE 1284 timing example

The IEEE 1284 timing is determined by the BBus clock and the Granularity Count register (GCR)

setting. In this example, the BBus clock is 50 MHz and the Granularity Count register is set to 25.

The basic time unit is

1/50 MHz x 25, which is 500ns.

Parameter Description Min Max Unit Note

IE1 Busy-while-Strobe 0 500 ns 1

IE2 Busy high to nAck low 0 ns

IE3 Busy high 1000 ns 2

IE4 nAck low 500 ns 3

IE5 nAck high to Busy low 500 ns 3

Table 35: IEEE 1284 timing parameters

IE1

IE3

IE5

IE2

IE4

Data[8:1]

nStrobe

Busy

nAck

1 2 ... 72 73 74 75 76 77 78 79 80 81 82 ... 87 88

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Digi NS9750 Uživatelský manuál Strana 77