Arty A7 vs Nexys A7

[Phil]

I have been looking at the Arty A7 and Nexys A7 boards and am confused about the FPGA part numbers listed for them.

The Arty A7 specifies the XC7A100TCSG324-1 part number.

The Nexys A7 specifies the XC7A100T-1CSG324C part number.

The numbers appear to be very similar, but there must be some difference in the two parts.  I have been unsuccessful finding anything that breaks down the part number for the Arty.  The Xilinx document "XA Artix-7 FPGAs Data Sheet: Overview" has the breakdown in ordering information for the part Nexys part number.  Are these in fact identical parts?

The Nexyx A7 board appears to be a re-spin of an earlier design.  When did this board come available?  What about the Arty A7 board, is it a more recent design?

I have searched the forum posts and did not find anything addressing this, so I decided to post my questions.  Thanks

[JColvin]

Hi @Phil,

Let's see if I can explain the differences for you:

There are a couple of variants between the boards. The Arty A7 has two chip size options, a -35T Artix 7 chip and a -100T Artix 7 chip. The Nexys A7 also has two size options in the -50T Artix 7 chip and the -100T Artix 7 chip. While the labels are slightly different (I'll find out which one is accurate and correct the other one, though I'm worried I'll find evidence for both), both of the -100T versions of Arty A7 and the Nexys A7 are the same chip.

With regards to the Nexys variants, the Nexys A7 is a re-branding of the Nexys 4 DDR, which in turn is a partial re-design of the Nexys 4 (which had received an EOL for one of it's memory chips that it used, which you can read a bit more about on this page). Time line wise, I believe the original Nexys 4 came out in 2013, the Nexys 4 DDR redesisn in 2014, and finally the rebranded Nexys A7 in 2018.

As for the Arty A7, it originally started out in 2015 as just the "Arty" that used an -35T Artix 7 chip. The product line has then expanded further over time to include a much wider variety, covered nicely in one of our blog posts here. I believe the Arty A7 also was rebranded back in 2018.

The biggest difference you'll find between the Arty A7-100T boards and the Nexys A7-100T boards will be the peripherals that are present on the boards (and correspondingly the demos based on those peripherals)

With regards to the Xilinx datasheet, you'll actually want to use this datasheet rather than the one you referenced which is exclusive to the automotive versions of the chips.

Let me know if you have any questions about this.

Thanks,
JColvin

[Phil]

Thanks @JColvin for addressing my questions.  This is good info.  I will be ordering the Arty A7 -100T.  I have a couple of more questions if you don't mind...

I want to make sure this board has the JTAG interface built-in, like I think it does from the description of the board features.  A while back I had ordered a Zynq kit from Avnet and it did not have JTAG built-in nor included with the kit, nor did it have any mention of needing one on whatever sales documentation we read about it before ordering.  We needed the HS2, which the user manual did mention.

I will be looking to use the Ethernet port on this board.  Is the MAC IP core freely available in Vivado or is this a licensed IP?  I will eventually need a 10/100/1000 speed MAC to go with my custom board design, if this is supported.  I understand that the Arty A7 has a 10/100 PHY.

Thanks

[jpeyron]

Hi @Phil,

The Arty-A7-100T comes with with a built in USB JTAG/UART (J10) programming circuit.You will not need an additional JTAG programmer like the JTAG-HS2  to configure the Arty-A7-100T. Here is the Arty A7 resource center.  Under Additional Resources there is a tutorial called getting started with microblaze servers that goes through making an ethernet echo server with the Ethernet lite IP Core (no cost). 

best regards,

Jon

[Phil]

Thanks @jpeyron for the info.  I just received my board and some IO modules so I will be digging through the resources you mentioned

[Phil]

Where can I download the schematic for the specific version of the board I have?  On the Arty A7 resource page, the schematic linked is rev C.1.  The board version I have is rev E (from the silkscreen on the back side just below the bar code sticker).  I noticed that some different parts are used between the two and would like to have the schematic specific to my board, if it is available.  Thanks

[jpeyron]

Hi @Phil,

Here is the schematic for the Arty-A7 rev E. Which can be found here.

best regards,

Jon

[Phil]

OK, thanks.  I had downloaded from the store page, which links to rev C.  The reference page links to rev E