JTAG Command Support with Security Enabled
Titanium and Topaz FPGAs support additional bitstream security by letting you disable JTAG commands completely or partially:
- JTAG Disable—Permanently disables the JTAG efuse instruction as well as all other JTAG commands except for the ones used to read device information.
- JTAG Disable Efuse—Permanently disables the JTAG efuse instructions only. Other JTAG instructions are not affected, for example, you can still perform debugging.
The following table shows the commands supported for each mode.
| Command | JTAG Disable | JTAG Disable Efuse | |||||
|---|---|---|---|---|---|---|---|
| Ti35, Ti60, Tz50 | Ti85, Ti135, Tz75, Tz100 | Ti90, Ti120, Ti180, Tz110, Tz170 | Ti165, Ti240, Ti375, Tz200, Tz325 | Ti85, Ti135, Tz75, Tz100 | Ti90, Ti120, Ti180, Tz110, Tz170 | Ti165, Ti240, Ti375, Tz200, Tz325 | |
| BYPASS |  |
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| DEVICE_STATUS | |
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| EFUSE_PREWRITE | – | – | – | – | – | – | – |
| EFUSE_USER_WRITE | – | – | – | – | – | – | – |
| EFUSE_WRITE_STATUS | – | – | – | – | – | – | – |
| ENTERUSER | – | – | – | – | |
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| EXTEST | – | – | – | – | |
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| IDCODE | |
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| INTEST | – | – | – | – | |
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| JTAG_USER1 | – | – | – | – | |
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| JTAG_USER2 | – | – | – | – | |
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| JTAG_USER3 | – | – | – | – | |
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| JTAG_USER4 | – | – | – | – | |
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| PROGRAM | – | – | – | – | |
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| SAMPLE/PRELOAD | |
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| USERCODE | – | |
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Refer to the following topics for details: