7.4.6 Control Fuses
The control fuse box includes 128 OTP (One-time programming) fuse bits. Only some of them are used to configure software security features (see table below). Reserved bits in the range 0 to 17 must not be modified. Bits from 18 to 128 are not used. The default status of all fuses is not set.
| Fuse Bit | Name | Description |
|---|---|---|
| 0 | ENCRNOTPLAIN | If it is set, Secure mode is active |
| 1 | READ_AES_KEY | If it is set, KEY_ENC and KEY_TAG cannot be read |
| 2 | WRITE_AES_KEY | If it is set, KEY_ENC and KEY_TAG can’t be written |
| 5 | READ_CONTROL | If it is set, CONTROL_FUSES can’t be read |
| 6 | WRITE_CONTROL | If it is set, CONTROL_FUSES can’t be written |
| 7 | READ_RAM | If it is set, memory ram can’t be read |
| 8 | RESERVED | Reserved |
| 9 | RESERVED | Reserved |
| 10 | FORCE_IVNBINC | If it is set, initialization vector and number of blocks must be used in the calculation of the signature |
| 11 | RESERVED | Reserved |
| 12 | RESERVED | Reserved |
| 13 | RESERVED | Reserved |
| 14 | RESERVED | Reserved |
| 15 | RESERVED | Reserved |
| 16 | DBG_DISABLE | If it is set, JTAG debug is disabled |
| 17 | DBG_DISABLE_SE | Reserved |