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Altera_Forum's avatar
Altera_Forum
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12 years ago

Passive Serial Tri-state

I am designing a Cyclone IV based board with an SPI interface that we would like to use to configure the FPGA with an MCU. We will configure the pins to toggle like Figure 8-16 (Device Handbook Vol ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

You suggested 'changing MSEL'. Altera states the MSEL pins should be connected directly to VCCA or GND and therefore should not be connected to any circuitry that can change them.

You won't need to do this to achieve what you need anyway. Ensure both DCLK and DATA are driven to a static level following configuration. Ensure you generate enough DCLKs cycles following delivery of the configuration data to clock the configuration state machine through and kick the device into life.

Cheers,

Alex