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I am new to FPGA and I am trying to get a working JTAG setup on Lattice iCE40 FPGA. The board I'm using is from Olimex and has iCE40-HX8K FPGA.

I'm using urjtag as PC application and tried with DirtJTAG and USB Blaster clones as programmer (flashed onto STM32 BluePill board). Olimex board didn't have populated pull-up resistors for JTAG so I soldered them (10k for TMS, TDI and TCK). But the end result is the same: I cannot get jtag to recognize FPGA, the error is:

jtag> cable UsbBlaster
Connected to libftdi driver.
jtag> detect
warning: TDO seems to be stuck at 1

Checked pinout of the JTAG connector and it's correct. Multimeter tests show that there is no short-circuit, no solder bridges, pullups are correct value and working and as expceted.

Tried my setup with Altera FPGA board and it's working, it will detect the FPGA. Also, tried eBay UsbBlaster clone and it's not working on iCE40, but works for Altera FPGA.

I can flash the external flash (with other tools and programmer), but I want to be able to use JTAG so I can flash onboard SRAM instead.

Any ideas/hints what might be wrong/what to try next?

JohnnySorocil
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1 Answers1

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iCE40 FPGAs do not have a JTAG interface.

CliffordVienna
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    Oh, than can explain some things. I was confused with dedicated JTAG pins in Olimex schematic, but now I guess they are for implementing JTAG in FPGA fabric. Thanks for the help and IceStom project :) – JohnnySorocil Apr 15 '18 at 17:17
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    [TN1248 iCE40 Programming and Configuration](http://www.latticesemi.com/~/media/LatticeSemi/Documents/ApplicationNotes/IK/iCE40ProgrammingandConfiguration.pdf) Revision History September 2012 01.5 Updated based on latest iCE40 information: ... — Removed JTAG references ... –  Apr 17 '18 at 01:49