MicroZed Chronicles: A Look at the AC701 Evaluation Kit

Editor’s Note: This content is republished from the MicroZed Chronicles, with permission from the author.

Artix-7 FPGAs are very interesting because they are the first devices with gigabit serial lines (GTP) that can run at 6.6 Gbps. This means we can work with interfaces like JESD204, SFP, and PCIe and of course if the device is being used on a development boards FMC high pin count as the GTP can be broken out.

Currently, we have several projects targeting Artix-7 devices. One will be flying on a rocket during launch and observing payload cleanliness while another is based around a Spartan-6 conversion. As such, I thought it would be a good idea to obtain an Artix-7 development board which covers current needs and those for future projects.  

The AC701 Evaluation Kit is based on the Artix-7 A200T device which is the largest FPGA in the family and offers 215,360 logic cells, 740 DSP, 365 RAM Blocks, 1 PCIe Gen2, and 16 GTP. To support this very capable device, the AC701 board provides the following memories, interfaces, and capabilities.

1. 1 GB DDDR3 at 533 MHz - This can be used to execute operating systems or large bare metal applications from. It can also be used to buffer data which is received from the FMC, SFP, PCIe, or Ethernet interfaces.  
2. 32 MB QSPI Flash – Used to store the FPGA application along with additional information and software applications and operating systems.
3. HDMI Out - Provides an Analog Devices ADV7511 HDMI transmitter that takes in parallel video which is then output by the AXI stream to video out IP core and IIC for mode configuration. 
4. LCD Display – 16 character by 2-line LCD useful for showing board status information like IP addresses. 
5. FMC-HP – A partially populated FMC-HP interface that provides 116 single ended or 58 differential pairs, four GTP transceivers, two GTP clocks, and two differential clocks.  
6. SFP+ Cage – This will accept SFP+ modules that can provide high-speed on and off board communication. 
7. SMA GTP Channel – One GTP broken out to SMA connectors providing TXp/TXn and RXp/RXn pairs. This makes accessing and characterizing performance of the links straightforward. 
8. PCIe 4 Lane – Enables high throughput communications using a motherboard / backplane. 
9. 200 MHz Oscillator – Reference oscillator for DDR3 memory. 
10. User Programmable IIC Oscillator – Programmable clocking frequency to provide frequencies as required for the prototyping at hand.
11. 10/100/1000 Mbps Ethernet – Network connectivity to the outside world.

These capabilities make for a very interesting development board which can be used for a range of applications from signal processing to networking and prototyping embedded applications. Of course, lower-cost development boards like the Arty A7 series can be used for prototyping if you don’t require gigabit transceivers or all of the other features. 

To explore the new AC701 board, I created a simple MicroBlaze project which provided both a simple hello world output and ran the lightweight IP stack that allows us to ping the board over Ethernet. 

Getting started with a MicroBlaze is very simple. Take a look at the video I did with Robert Feranec to see a step-by-step live build. It will walk you through the MicroBlaze creation process and describe several of the key elements.  

This example contains several IP cores which we commonly use in addition to the LWIP echo server example running in software. 

One of the nice things about the AC701 is that it allows us to leverage the 1 GB of DDR to run PetaLinux on a MicroBlaze system.

I really like this board and I love the FMC/HDMI combination which is also similar in the SP701. I am planning to leverage the Pcam FMC and four Pcam 5Cs to create an image processing solution that will work on both boards.