User Guide

Hardware and Software Design • Manufacturing Services
P a g e 28
BIS2_COSEDGE
[$44] BiSerial II COS Edge Definition Register
Change of State Edge Register
DATA BIT DESCRIPTION
31-16 Spare
15-8 falling7-0
7-0 rising7-0
FIGURE 14 PMC BISERIAL-II COSEDGE REGISTER BIT MAP
Rising when set for a channel enables that COS state-machine [if enabled] to look
for rising edge transitions and to set the status bit when found.
Falling when set for a channel enables that COS state-machine [if enabled] to look
for falling edge transitions and to set the status bit when found.
The COS state machine operates at the PCI frequency and can handle single width
pulse transitions. If a signal goes from low to high to low on successive clocks
then both edges will be found if the COS is enabled and the rising and falling bits
are set. The state-machine can be altered if the user wants to have some
filtering action employed. There is plenty of room in the FPGA for adding
minimum count processing etc. Please contact Dynamic Engineering with your
requirements.