Information on readme how to upload bitstream to FPGA?

[Kazhuu]

Hello! I'm relative new to Xilinx FPGAs and ordered one of these boards. I'm wondering what is the best way to actually do some FPGA development on this board? I think I can put the bitstream file to SD card and let linux upload it to FPGA on boot but cannot find any information about this. Also someone on Reddit mentioned that you need JTAG FPGA programming cable from Xilinx. I guess this would be the best way to do the development? But the cable itself cost something like 80€ I think.

I've used Altera's development boards earlier which can be used with USB cable instead. Thank you!

[xjtuecho]

Maybe you need a Digilent JTAG-SMT2，the FT232HL_v20.5.31.pdf in this repo is enough. cost about 8$

[Kazhuu]

Thanks! With this information I was actually able to do some research and found web page describing programming solutions. I also had a look at FT232HL board you mentioned and was thinking could this Adafruit one serve similar purpose? Of course with this you have to connect the pins individually.

[tpecar]

Hi, I'm probably from the same bandwagon as @Kazhuu.

With a bunch of these on the way I'm also in the process of figuring out how to use them 🤣

The cheapest way to get going is probably to just build the SD card image and boot the board from that. Most examples available for this board go this way

• https://www.jianshu.com/p/b83c663ecaaa
• https://gitee.com/actionchen/ebaz4205_hw/blob/master/Doc/ebaz4205_introduce.md
• https://www.youtube.com/watch?v=b6g5tNZZnVc

However, in order to debug a baremetal application running on PS (ARM core) and to not loose sanity swapping SD cards, I also want to figure out how to use JTAG.

The easy and expensive way of doing this

The Digitlent JTAG cables are the official cables that are supported by Xilinx tools. If you want the minimum amount of fuss, get one of these.

However, given that they are only glorified FTDI dongles programmed with configuration blessed by Xilinx, it makes me a bit mad spending $60 for one of these.

The cheap and finnicky way of doing this

While I couldn't find a product that uses the exact design specified in FT232HL_v20.5.31.pdf, I suppose that most generic FTDI JTAG dongles are applicable here.

---

If you have a FT232Hx, 2232Hx, etc. (basically any chip that has MPSSE) dongle with an onboard EEPROM, you can program it with a license to make it look like an official dongle.

See the discussion below.

The rest of the post discusses open source tools and methods to program the device.

---

You can then use OpenOCD or xc3sprog to download the bitstream to the fpga (provided that you have boot mode pins set to JTAG - these are the same pins @xjtuecho suggests to change to get SDcard boot).

There's a couple of gotchas however:

• xc3sprog is only capable of setting up the PL (FPGA) side, PS (ARM core) is uninitialized

• OpenOCD has support to set up PL / PS sections

  • OpenOCD page has configuration files for Zynq but it needs to be adapted to your specific chip
  • Zynq-RS project has configuration files set up for Z7-10

  but is not supported by Xilinx, so there's probably some effort required to get a decent debugging environment

• none of these metods give you access to ILA

Then you have the Xilinx Virtual Cable (XVC).
It should give you access to ILA and debugging functionality, so it seems to be the most interesting method.

Instead of talking to the debug probe directly, the Xilinx tools talk to a XVC deamon over TCP/IP, which can run on your system or some other device, which is actually connected to your target

• original XVC deamon and its sister project run on your development system and talk to the target via FTDI2232 (essentially bypassing the silly restrictions). However, these projects seem to be inactive.
• Xilinx has reworked this code to run directly on a Zynq platform, so if you have more than one board, you can use one as a debug probe.
• somebody has ported the Xilinx example on the Raspberry Pi so you can try that.

[Kazhuu]

@tpecar thanks for the very detailed answer! This really helps people like me to get started and learning. Very appreciated! I think I might end up buying a cable from Digilent because it can also be used in the future with different boards. And I'm interested in the debugging support which is quite mandatory when doing anything more complicated.

One thing I'm wondering. If I buy JTAG-HS3 instead of JTAG-HS2. HS3 has support for PS_SRST pin resetting the processor during debugging. Although I checked the schematics of this board and it seems this pin is not connected to JTAG header. I'm guessing if you want PS_SRST pin support then you'd need to modify the board. Here is good explanation of PS_SRST.

[tpecar]

Well, given that they sell both JTAG-HS2 and JTAG-HS3 for the same price, I guess you select the one that better fits your use case.

HS2 supports 2-Wire JTAG, but since we already have standard JTAG routed out, this is a non-issue.

HS3, as you mentioned, has an open drain output which the Xilinx tools can use for PS reset.

The PS_SRST_B (B10 on CLG400 package) is routed out to R2430 (pullup to VCC) which is perfect - just run a bodge wire to the JTAG connector (pin 12, 14 of the connector seem to be disconnected).

HS3 routes SRST on pin 14, so connect to that and should be plug & play

[Kazhuu]

Thanks you for you detailed answer! I'll order one and try it out. Sorry might be beginner question but what I understood that HS3 has open drain outputs, meaning that I have to connect it to VCC pull up like you said. So in this case I need to connect from the left side of the resistor to pin 14 like so.

[tpecar]

Yep, that should work.

It obviously needs to be tested, and I probably have a good 2 months before I get the boards, so if you can try that earlier I'll appreciate your report.

Once it gets tested, we can consider integrating it into the readme.

[Kazhuu]

Sounds good. I can test it but it might not be very soon because I'm not at home during Christmas holidays and getting that cable to Finland will take some time delivered. I'll report here when I've tested this.

[tpecar]

getting that cable to Finland will take some time delivered

Just in case you didn't notice, Digilent has European distributors - you can get the cable at Farnell for example.

[regymm]

Actually, you can download the bitstream over ethernet in u-boot. So no need to solder SD card slot or buy expensive JTAG downloaders. UART is still needed though.

Set up a tftp server on host computer and in u-boot use command similar to this:

<press d>
setenv serverip 192.168.6.6
setenv ipaddr 192.168.6.136
tftpboot 0x100000 bd_hello_wrapper.bit.bin
fpga load 0 0x100000 0x1fcba0

reset

Bitstreams must be converted to bin files to run, use this tcl script:

proc gen_bin {bit} {
    set filename [file rootname [file tail $bit]].bif
    set fileId [open $filename "w"]
    puts $fileId "all:"
    puts $fileId "{"
    puts $fileId "  $bit"
    puts $fileId "}"
    close $fileId
    #exec bootgen -w on -image $filename -arch zynqmp -process_bitstream bin
    exec bootgen -w on -image $filename -arch zynq -process_bitstream bin
    puts "$filename created successfully"
}

Also, as this board's ethernet is connected to PL instead of PS, the ethernet connection will fail after downloading bitstream, which is quite annoying. So EMIO and the PS must be specially configured(even if not used) to keep net connection working after programming.

Somewhat detailed instruction can be found in this article on my blog(at the end is the ethernet part):
https://www.ustcpetergu.com/MyBlog/experience/2020/07/01/ebaz-4205.html
It's in Chinese but I ran a google translation test and it seems OK.

[regymm]

And about JTAG downloader, I did by one later. But of course not the expensive official one. I just picked a CJMCU FT232HL(the one with purple PCB, which is quite common) module and flashed the EEPROM. Similar to this: https://gist.github.com/rikka0w0/24b58b54473227502fa0334bbe75c3c1

The firmware between FT232 and FT2232 may be a little different so the gist may not work out-of-the-box, but I got it working at last. Only cost me 30RMB.

[tpecar]

Thank you @ustcpetergu for the info on downloading bitstreams over Ethernet. I suppose this uses the u-boot of the original miner firmware which is programmed on the flash chip.

Regarding JTAG dongles, it is possible to flash the EEPROM of a generic dongle with Digilent firmware. This is against their license, which isn't that much of a problem in case of hobby / personal usage, but it might become important in other settings.

Regarding FT232, correct me if I'm wrong, but I thought you required FT2232 due to MPSSE (which has JTAG capability), at least for interfacing with original Xilinx tools. Other unofficial tools which use FT232 do so by bit-banging the interface.

[regymm]

Yes, this method uses the u-boot in on-board NAND(or NOR flash? not very sure).

And as far as I know, FT232H works too. My Vivado detected my FT232H and successfully recognized the 7010 chip when ebaz4205 is connected. I haven't tried anything like bitstream downloading or ILA though(I trashed my board when trying to remove the BGA xc7z010 chip, so won't have any chance to test).

But as better evidence, the 7010 board by Alinx does use FT232HL as their JTAG chip. I don't have this board but on their user guide, the schematic on page 12 shows so.
http://www.alinx.vip:81/ug/AX7020_UG.pdf

One difference I know is that FT2232H is dual-channel so you can have JTAG and USB-to-UART together just using one USB cable, like on Digilent board ZYBO or PYNQ. FT232H is a single-channel one so another standalone USB-to-UART chip is required, in the Alinx case, CP2102 is used.

[tpecar]

Ok, thank you very much for the clarification!

And you're right, FT232H (which is completely different from FT232R, so suffixes are important) has MPSSE. So, provided you configure its EEPROM (again, hobby/personal use only), it should work with Xilinx tools.

I guess that this is the method that @xjtuecho has referenced initially, so we've come full circle 🤣
I'll provide clarifications to my previous posts.

Thank you for also providing a concrete example.

[ryanm101]

There are some good tutorials here: https://www.programmersought.com/article/78153940676/

https://www.programmersought.com/article/65574959208/

HDMI: https://www.programmersought.com/article/80046040945/ (shows pinout for DATA1-3)

Bonus points if anyone actually manages to download and reupload anything from that CSDN site