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Altera_Forum
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15 years ago

CPLD I/O's during power up

Hello everybody, I am using a Max II EPM570T100A5 CPLD; in our design the CPLD controls 4 MOSFET drivers for a fullbridge, thus it is critical that these outputs on the CPLD remain at GND dur...
Altera_Forum's avatar
Altera_Forum
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15 years ago

Thinking about the problem should clarify, that Quartus can't control the state of unconfigured IOs, because this state is exclusively determined by the MAX II hardware.

The minimum and maximum weak pull-up values are specified in the datasheet. Depending on the threshold of the connected devices, you'll need 1 to 2.2k pull-down resistors for safe low-level during power up.