Honored ContributorIs the on chip termination available on these devices good enough to eliminate external source termination? The reason I ask is that it does not look like it is being used on the kit boards - I still see some rpacks being used for source termination. I also remember some negative comments for this feature on earlier chip families.
Honored ContributorI talked with a guy from Altera a couple of months ago and he said it was a coin flip on which way to go. He seemed to like it on the EP3Cxx parts. I just built a board without the rpacks so I hope he was right. But, with just the EP3C25, ISSI SRAM, and Intel P30 flash I don't have more then 1.7" length on any trace. I basically took the OrCAD files that come with the Cyclone III starter board and took out the USB blaster and DDR. Then I added an xPort, some opto coupled I/O and a board/board connector to get to an A/D and stepper controller on a second board. Maybe I'll know in a few weeks it the termination is OK.
Good Luck AlHonored ContributorThis sounds a lot like what I plan to do, but because of time constraints I am thinking of using the kit board as a plug-in module to our 1st prototype.
One downside to this family and board is that it requires at least two more regulators. Did you decide to keep the 2.5v for the board/board signals or go with 3.3v?Honored ContributorI went to 3.3V for the I/O to guarantee the levels for the stuff I have on the other boards in the stack. The RAM used 3.3V so as long as it was there the call was easy. 3.3V, 2.5V, 1.8V, and 1.2V for just the cyclone, ram, and flash ... what a pain.
I used a Cyclone II NIOS board for the first run like you're doing with the Cyclone III. This is the first time that I did a 324 pad BGA and it took a ton of time to lay out the new board. What all are you adding to the starter board? AlHonored ContributorA couple A/Ds, some pulse generator circuitry, spi, eeprom, gpio. I'd prefer to change the 2.5v to 3.3v for all the IO I am using, but I guess I am stuck with 2.5v if I want to use the starter board as a module. I'll have some 2.5v to 3.3v interfaces as well as 2.5v to 5v. Not sure what chips I'd need for this yet.
Honored ContributorDo a Google search for this part ... 74vcxhq163245 It has 2 voltages Vcca and Vccb. It translates between the different logic levels and it's fast.
AlHonored ContributorYes, that is a good one. As far as fast goes, a part like the TI sn74cb3t3384 bus latch can't be beat. Which CII board did you originally use? Did it work well for you? If you did not use an HSMC connector on your new board what did you use?
Honored ContributorThe customer got me the NIOS II dev kit that goes for $995 and includes a year of registration on the software.
My I/O circuits were developed connecting to the 0.1" pin headers on that Altera board. On my new board I just used .Samtec 05" c/c dual row parts. 500K samples/sec on the ADC is the fastest thing on the other boards so there isn't any need for super good connections/layout to the I/O boards. I just wanted the Cyclone III with multiple NIOS cores to be able to have I/O operations be autonomous. Al
