Introduction

ADLINK PCI-8554 is a 12-CH 16-bit timer/counter and digital I/O cards. It provides ten independent timer/counters and one cascaded 32-bit timer. The clock source for each timer/counter can be software selected from the cascaded 32-bit timer, external clock source, timer/counter output of the last channel, and the on-board 8MHz clock. The flexible architecture makes it easy to re-configure the hardware; for example, up to ten timer/counters can be cascaded to form a 160-bit timer/counter. The hardware can also generate interrupts from either the external interrupt sources or the output of the cascaded 32-bit timer. The programmable de-bounce filters provide eleven channels of glitch-filtered external clock inputs for timer/counters and the external interrupt input. This feature further improves the reliability for counting applications.