Brain Reset Configuration: "Active High" And "Active Low - OPTO 22 PCI-AC51 User Manual

CHAPTER 3: INSTALLING AND USING THE SDK

Brain Reset Configuration: "Active HIGH" and "Active LOW"

Each Pamux brain has a jumper to configure whether the brain will reset when the reset line is HIGH
or LOW. This is referred to as reset "Active HIGH" or reset "Active LOW".
If the brains are jumpered for reset "Active HIGH", then the system will be "in reset" (the brains will be
reset) when the reset line is HIGH. The brains will function normally (not be reset) when the reset
line is LOW.
Similarly, if the brains are jumpered for reset "Active LOW", then the system will be "in reset" (the
brains will be reset) when the reset line is LOW. The brains will function normally (not be reset) when
the reset line is HIGH.
You must determine whether you want your Pamux system to operate with reset Active HIGH or
reset Active LOW. Then consistently set the reset jumper on each brain in the system to match your
choice; all brains must use the same reset configuration. One consideration is how you want your
system to function if the computer loses power. Without power to the computer, the PCI-AC51 or
PCIe-AC51 cannot drive the reset line high, so by default it will be low. You would want to analyze
your system needs to determine what is necessary for your system to automatically go into failsafe
mode.
21
21
PCI-AC51 and PCIe-AC51 User's Guide