Cyclone 10 LP AS Configuration Problems
I am having problems with a Cyclone 10 LP running a Nios processor that is writing spurious data to its configuration device on power down.
I'm using a 16Mbit SPI configuration device and the EPCQ Controller 2 to control it.
The device is set to configure in AS mode and the dual use pins are set to Regular IO on configuration completion as we read/write to part of the configuration device for permanent storage.
I have seen on an oscilloscope that the Chip select and Data lines to the configuration device start toggling on power down for about 600µs. I've also seen that the clock signal remains active even after the device has configured.
I've performed a test where I set the dual use pins to Compiler Configured and this stops the DCLK when configuration is complete.
I've looked at a previous project using a Cyclone III and the EPCS Controller with the dual use pins set to Regular IO and have seen all of the configuration signals become and stay static after configuration has ended.
Does any one have any ideas what might be going on? Especially why is the clock signal remaining active after configuration?
Thanks