PCI-1718 Series User Manual 72
U/B Unipolar/bipolar mode indicator
0 Bipolar mode
1 Unipolar mode
MUX Single-ended/differential channel indicator
0 8 differential channels
1 16 single-ended channels
INT Data valid
0 No A/D conversion has been completed since the last time the INT
bit was cleared. Values in the A/D data registers are not valid data.
1 The A/D conversion has finished, and converted data is ready. If the
INTE bit of the control register (BASE +09H) is set, an interrupt
signal will be sent to the PC bus through interrupt level IRQn, where
n is specified by bits I2, I1 and I0 of the control register. Though the
A/D status register is read-only, writing to it with any value will
clear the INT bit.
CN3 to CN0 When EOC = 0, these status bits contain the channel
number of the next channel to be converted.
Note:
If you trigger the A/D conversion with the on-board pacer or an external
pulse, your software should check the INT bit, not the EOC bit, before it
reads the conversion data.
EOC can equal 0 in two different situations: the conversion has com-
pleted or no conversion has been started. Your software should therefore
wait for the signal SNT = 1 before it reads the conversion data. It should
then clear the INT bit by writing any value to the A/D status register
BASE+08H.