# HiFive FE310-G002 JTAG on Board HiFive1 Rev B

**URL:** <https://forums.sifive.com/t/hifive-fe310-g002-jtag-on-board-hifive1-rev-b/4187>\
**Category:** HiFive1 Rev B\
**Created:** [November 10, 2020, 7:26pm UTC](https://forums.sifive.com/t/hifive-fe310-g002-jtag-on-board-hifive1-rev-b/4187 "2020-11-10T19:26:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![EdgardoGho](https://avatars.discourse-cdn.com/v4/letter/e/a8b319/32.png) [@EdgardoGho](https://forums.sifive.com/u/EdgardoGho)\
**Post date:** [November 10, 2020, 7:26pm UTC](https://forums.sifive.com/t/hifive-fe310-g002-jtag-on-board-hifive1-rev-b/4187/1 "2020-11-10T19:26:44Z")

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Hello,  
I have 5 chips (FE310-G002) and I would like to build 5 PCBs with this chip.  
Its for a university project to test RISC-V chips with JTAG.  
I also have for testing and troubleshooting a HiFive1 Rev B board and a Sparkfun Red V board (very similar to the HIFive1).

Looking at both schematics (for HiFive1 and RedV) I see there is a USB-JTAG IC which works great and I can debug perfectly using openOCD.

But on my final board I want to use a third party tool (BusPirate) which is also a USB-JTAG and it is supported by OpenOCD.  
My idea is to create a small board with the FE310-G002 , the Quad SPI memory, power regulators ICs and a lot of GPIO pins. I plan to leave the JTAG pins (we have FPGA programming experience so we have dealt with JTAG before) accesible so we can connect with the USB-JTAG interface.

So here is the question… I see that both the HIFive1 and RedV board have the JTAG pins accesible, but they are connected both to the FE310-G002 and the USB-JTAG IC.  
I want to know if I can connect in parallel my own USB-JTAG and simply skip using the onboard USB-JTAG IC.  
The idea is to test this BusPirate with OpenOCD before manufacturing the PCBs with the FE310-G002 on them.

Thanks,  
Best Regards,  
Edgardo

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<div class="post-metadata">

**Author:** ![bruce](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.sifive.com/bruce/32/452_2.png) [@bruce](https://forums.sifive.com/u/bruce)\
**Post date:** [November 11, 2020, 1:21am UTC](https://forums.sifive.com/t/hifive-fe310-g002-jtag-on-board-hifive1-rev-b/4187/2 "2020-11-11T01:21:17Z")

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The HiFive1 RevB has a JTAG header between and inboard from the power LEDs and the Arduino power/reset headers.

Pretty sure it’s there to be used if you want to. Page 9 of the Getting Started doc says you can use it.

4.3 External JTAG probe header  
The HiFive1 Rev B is populated with a 2x5, 0.05" pitch connector for use with an optional external  
JTAG probe. This option would replace the on board Segger J-Link OB JTAG function with  
an external JTAG debugger. This JTAG connector is compatible with the MIPI-10 0.05 inch  
connector specification, as mentioned in the RISC-V debug specification.

> **[4f5a7851-1b52-463b-a293-f352036bc809\_hifive1b-getting-started-guide\_v1.1.pdf](https://sifive.cdn.prismic.io/sifive/4f5a7851-1b52-463b-a293-f352036bc809_hifive1b-getting-started-guide_v1.1.pdf)**
>
> 792.13 KB