User`s manual

PK2100

3-8 s I/O Configurations

exact time, within a few microseconds, at which an event occurs by

programming the DMA channel to store one byte and then interrupt the

count. The interrupt routine can read the most significant part of the PRT

counter and any software extension of this counter. In general, the

maximum count is 65,536, which can be extended by software to larger

counts if the counting speed is not higher than about 10 kHz.

The capabilities of the counters are summarized below.

 Counters measure the time at which a negative edge occurs with a

precision of a few microseconds. The measurement can be repeated

hundreds of times per second. A minimum time must occur between

successive events to allow for interrupt processing.

 Counters measure the width of a pulse by counting (up to 65,536) at a

rate from more than 100 kHz to 300 Hz. This provides 16-bit accuracy

in the measurement of pulse widths.

 Counters count negative-going edges for up to two channels. The

maximum count for high-speed counting (5 kHz to more than

100kHz) is 65,536. The maximum count for low-speed counting is

unlimited.

High-Sensitivity Differential Analog Input

One high-sensitivity analog input is available. This input has a differential

input with a gain of 10 compared to the universal input. This input is

useful for devices requiring higher input sensitivity, for example, ther-

mistors or RTDs in a bridge. Although the high-sensitivity input has 10

times the gain and accuracy, the dynamic range is necessarily 10 times

less, since the number voltage steps available from the conversion (1024)

does not change. Figure 3-8 shows the high-sensitivity input circuit.



to Comparator 8

AD+

R11

RP5B

AD

RP5A

to Comparator 7

7th Universal Input

470 kΩ

47 kΩ

470 kΩ

Figure 3-8. High-Sensitivity Differential Analog Input