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Article Details

ID: 2045
Case Type: faq
Category: Architecture
Related To: IO
Family: ispMACH 4000

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I have 75 5V inputs to an ispMACH4000 device. Which I/O type should I use between LVTTL or LVTTL_5V?

Two 5V support options, \u201CPCI_5V\u201D and \u201CLVTTL_5V\u201D were added to the supporting I/O type constraint list for the ispMACH\u2122 4000 device families. Since the LVTTL I/O type's maximum VIH is 3.6V, you must use the LVTTL_5V I/O type to support 5V inputs.  

You can assign these options to input pins via the Constraint Editor to achieve 5V inputs for the PCI and LVTTL I/O standards. The software will assign each 5V input to a bank that has a 3.3V VCCO.

Each ispMACH 4000 family device can support up to 64 5V inputs. Due to this limitation, you will need to use two ispMACH 4000 family devices if you need to use 75 5V inputs.