Program using a JTAG Bridge

About this task

Programming with a JTAG bridge is a two-step process: first you configure the FPGA to turn it into a flash programmer (.bit) and second you use the FPGA to program the flash device with the bitstream (.hex).

The SPI Active using JTAG Bridge mode (formerly named SPI Active using JTAG Bridge (New)) has pre-built flash loader (.bit) files that you can use. These .bit files do not require an external clock source. You can still use your own .bit file if you choose to do so.

Note: The JTAG bridge modes were changed in the Efinity software v2025.1. If you are using an older version of software and want to use the SPI Active using JTAG Bridge (Legacy) mode, refer to Appendix: Program using a JTAG Bridge (Legacy).

The JTAG bridge bitstream files bundled with v2025.1 and higher can only be used with v2025.1 or higher. You cannot use older bundled JTAG bridge bitstream files with v2025.1 or higher, and you cannot use the v2025.1 or higher bundled files with older software versions. If you need to use the older bundled files, use the Programmer v2024.2.

Tip: If you would like to incorporate the RTL files for the new flash loader into your own design, use the JTAG to SPI Flash Bridge core in the IP Manager.

The Titanium and Topaz .bit files include a custom JTAG USERCODE in the bitstream:

Single flash .bit files—0x96C09A03
Dual flash .bit files—0xC07FCFE2

Note: For Titanium Topaz FPGAs, the Programmer automatically loads the .bit file based on the FPGA target. The Programmer has separate pre-built .bit files for JTAG bridge mode

For Trion FPGAs, you need to specify the pre-built file to use.

Figure 1. SPI Active Using JTAG Bridge Options

To program using a JTAG bridge:

Procedure

Choose the USB Target.
In the Image box, click the Select Image File button to browse for the .hex file to program the flash device.
Choose the SPI Active using JTAG Bridge or SPI Active x8 using JTAG Bridge programming mode.
Turn on the Auto configure JTAG Bridge Image option.
For Titanium Topaz FPGAs, the Programmer automatically loads the .bit file. Skip step 5 if you want to use the pre-loaded .bit file.
Specify your own .bit file.
1. In the Programming Mode box, click Select Image File.
2. The Open Image File dialog box opens to a directory of available pre-built .bit files.
  Choose the file for your FPGA (Trion), or browse to find your own .bit file.
  
  The Programmer remembers which file you specify and uses it automatically the next time you run the Programmer.

Choose the SPI Active Options and JTAG Options.

Option	Description
Select Flash	x8 mode only. Choose whether to use the upper flash, lowre, flash, or both.
Starting Flash Address	Specify the address if other than the default.
Flash Length	Specify the length if other than the default.
Erase Before Programming	Default: on. When turned on, the Programmer erases the flash device before re-programming it.
Select Verify Method	Normal verify—The FPGA computes an on-chip hash from the read back flash data to perform verification. Normal verify is significantly faster than in the Programmer v2024.2 and lower (so much faster that you might think it did not do anything). Fast verify—Similar to normal verify, but requires a SPI x4 width (quad mode). The Programmer cannot detect whether your board is using quad mode; if your board is not using it and you try to use fast verify, programming will fail. Skip verify—Do not verify the flash.
Device Select	Choose the JTAG device ID of the FPGA to program.
JTAG Clock Speed	Choose a speed or specify a custom one.

Click Start Program. The Programmer first configures the FPGA and then programs the flash device.

Results

Important: If you are using the Titanium Topaz RSA bitstream authentication security feature, you need to use a signed .bit file. Copy the bundled .bit file from <Efinity version>/pgm/fli/titanium/pgm/fli/topaz to another directory and sign it. Then point to the signed .bit file in the Programmer. You can also create your own .bit file if you prefer.

Refer to Using the Efinity Bitstream Security Key Generator for information on signing existing .bit files.

Efinix strongly recommends you to disable JTAG if you are using the security features to achieve the highest security level. While disabled, you can still program the flash with JTAG Bridge by connecting to a soft JTAG tap IP and four GPIOs. Refer to: