Agilent Technologies 4294A Service Manual download pdf (Page 123)

100

101

Chapter 9 123

Communication with External Equipment (Using the I/O Ports)

Using the I/O Ports

1. Chapter Title

2. Chapter Title 3. Chapter Title

9. Communication with

5. Chapter Title

Exernal Equipment

(Using the I/O Ports)

Input/output port

The 24-bit I/O port of the 4294A consists of 2 sets of output ports and 2 sets of

bi-directional ports as shown below.

• Output port

Port A: 8-bit width (LSB: A0, MSB: A7)

Port B: 8-bit width (LSB: B0, MSB: B7)

The signals provide TTL level and latched when used as output.

• Bi-directional port

Port C: 4-bit width (LSB: C0, MSB: C3)

Port D: 4-bit width (LSB: D0, MSB: D3)

The signals provide TTL level and latched when used as output. To select the input/output

direction, use the GPIB command. At power-on, both port C and port D are set to input.

You can combine some of the above 4 ports to use them as 4 kinds of ports as shown below.

• Bi-directional port

Port E: 8-bit width (port C + port D, LSB: C0, MSB: D3)

• Output port

Port F: 16-bit width (port A + port B, LSB: A0, MSB: B7)

Port G: 20-bit width (port A + port B + port C, LSB: A0, MSB: C3)

Port H: 24-bit width (port A + port B + port C + port D, LSB: A0, MSB: D3)

Control signal lines

The 24-bit I/O port has 9 kinds of output signal lines and 1 kind of input signal line. The

signals except for the power line provide TTL level. Each signal is described below.

Port C status output, port D status output

Go LOW when Port C and port D are both set to input ports; HIGH when set to output

ports. These output signals notify external equipment of the input/output settings of port C

and port D.

Write strobe output for output ports

When data is outputted to one of the output ports, this write strobe output falls to indicate

that data is outputted the I/O output port for external equipment. The pulse width is 10 μs

(typical).

Figure 9-3 shows the relationship between the write strobe output and data

output.

Figure 9-3 Relationship between the write strobe signal and data output

INPUT1 input

1 2 ... 118 119 120 121 122 123 124 125 126 127 128 ... 517 518

Comments to this Manuals

No comments

Agilent Technologies 4294A Service Manual Page 123

Comments to this Manuals

Related products and manuals for Multimeters Agilent Technologies 4294A