Tabor Electronics 5251, User Manual

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TE5251
User Manual
4-30
Figure Chapter
4
-1, Definite Length Arbitrary Block Data Format
Transfer of definite length arbitrary block data must terminate with the EOI bit set. This way, carriage-return
(CR – 0dH) and line feed (LF – 0aH) characters can be used as waveform data points and will not cause
unexpected termination of the arbitrary block data.
•
<binary_block> Represents waveform data.
The waveform data is made of 16-bit words however, the GPIB link has 8 data bas lines and accepts 8-bit
words only. Therefore, the data has to be prepared as 16-bit words and rearranged as two 8-bit words
before it can be used by the 5251 as waveform data points. The following description shows you how to
prepare the data for downloading to the 5251. There are a number of points you should be aware of before
you start preparing the data:
1. Each channel has its own waveform memory. Therefore, make sure you selected the correct active
channel before you download data to the generator
2. Waveform data points have 16-bit values
3. Data point range is 0 to 65,535 decimal
4. Data point 0 to data point 65,535 corresponds to full-scale amplitude setting.
Figure 4-2 shows how to initially prepare the 16-bit word for a waveform data point. Data has to be further
manipulated to a final format that the instrument can accept and process as waveform point.
D7 D6 D5 D4 D3 D2 D1 D0
high-byte
D8 D9 D10 D11 D12 D13 D14 D15
MSB LSB low-byte
Figure 4-2, 16-bit Initial Waveform Data Point Representation
Figure 4-3 shows the same 16-bit word as in Figure 4-2, except the high and low bytes are swapped. This
is the correct format that the 5251 expects as waveform point data. The first byte to be sent to the generator
is the low-byte and then high-byte.
D2 D1 D0 D3 D4 D5 D6 D7
high-byte low-byte
D8 D9 D10 D11 D12 D13 D14 D15
Figure 4-3, 16-bit Waveform Data Point Representation
Parameters