Input/Attenuation Selection (R14)

The Input/Attenuation Register R14 selects which analog input (A or B) will be captured and what amount of attenuation will be applied before A/D conversion.

Four bits are used to program these features:

Bit NameValue Meaning

1/0Attenuation Range0Attenuation Range 1.
1Attenuation Range 2.
2Attenuation Range 3.
3Attenuation Range 4.
2Channel Select0Input from channel B.
1Input from Channel A.
3zz-clk Level0Always set to one.

There are two sets of these bits, one in each of the upper and lower nybbles of R14.

One or both sets may need to be programmed depending on the selected trace mode.

Recall that there are two pairs of A/B analog inputs, one pair via the BNC connectors on the front panel, the other pair via the POD. The attenuation actually applied depends on which inputs are used, and if BNC, whether a x10 probe is connected:

Attenuation RangeBNC x1BNC x10POD