Cyclone V IO's can't work on any peripherals， even I2C memory.

[ZLu001]

same circuits and HDL for cyclone V and IV IO's. it works on cyclone IV, but can't work on Cyclone V for any peripherals, even I2C memory. I tried program the IO's for different voltage setting, but it does't work. using oscillator to see, seems the lower level(logical 0) is going up gradually along the transmit line . 

The I/O ports are gong out directly from FPGA chip then be connected to an I2C chip or register chip.

any one can help?

Thanks

[a_x_h_75]

Have you constrained your IO for your Cyclone V project? Have you check the report files? It sounds like the pins you are monitoring with your 'oscillator' (oscilloscope?) are unasigned and are probably floating.

Cheers,

Alex

[SreekumarR_G_Intel]

Hello Zen Lu, As Alex mentioned , Did you get chance to check the IO pins constraints . Can you let me know how i can help for the same ? Thank you , Regards, Sree

[ZLu001]

Hi, Thanks all

finally I found if I slow down the clock to 500KHz, It works normally, but in cyclone IV, it works well at 1.2MHz.

Thanks any way, I can bear the slow.