How to use SDRAM on de2-70 board?

just quick reply.

> Do I have to connect from coe_out to LED for checking coe_out by using LED out?

you don't have to connect to the LEDs, but if you connect to LEDs

instead of "out_port_from_the_led_pio".

you can control LED from NiosII.

if you send a value like 0x01 via NiosII ( refer to address from SOPC )

you can lite one of led on the board.

but you don't have to connect to the LEDs.

just leave them and set a value to the address( of your IP-core )

and read it as I told you in the document.

you can read the value. which means your value is saved on the register of your own IP.

all right, I will write next document for your next step.