Chapter 2. API Reference
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38 ADC1_TP_HIGH EFUSE_BLK3 103 9
39 ADC2_TP_LOW EFUSE_BLK3 112 7
40 ADC2_TP_HIGH EFUSE_BLK3 119 9
41 SECURE_VERSION EFUSE_BLK3 128 32
42 MAC_CUSTOM_VER EFUSE_BLK3 184 8
Used bits in eFuse table:
EFUSE_BLK0
[2 2] [7 9] [16 18] [20 27] [32 87] [96 97] [105 109] [111 111] [136 144] [188␣
,→191] [194 194] [196 196] [198 201]
EFUSE_BLK1
[0 255]
EFUSE_BLK2
[0 255]
EFUSE_BLK3
[0 55] [96 159] [184 191]
Note: Not printed ranges are free for using. (bits in EFUSE_BLK0 are reserved for␣
,→Espressif)
Parsing eFuse CSV input file $IDF_PATH/components/efuse/esp32s2/esp_efuse_table.
,→csv ...
Verifying eFuse table...
The number of bits not included in square brackets is free (bits in EFUSE_BLK0 are reserved for Espressif). All
fields are checked for overlapping.
2. Fill a line for field: field_name, efuse_block, bit_start, bit_count, comment.
3. Run a show_efuse_table command to check eFuse table. To generate source files run
efuse_common_table or efuse_custom_table command.
Debug eFuse & Unit tests
Virtual eFuses The Kconfig option CONFIG_EFUSE_VIRTUAL will virtualize eFuse values inside the eFuse Man-
ager, so writes are emulated and no eFuse values are permanently changed. This can be useful for debugging app and
unit tests. During startup, the eFuses are copied to RAM. All eFuse operations (read and write) are performed with
RAM instead of the real eFuse registers.
In addition to the CONFIG_EFUSE_VIRTUAL option there is CONFIG_EFUSE_VIRTUAL_KEEP_IN_FLASH option
that adds a feature to keep eFuses in flash memory. To use this mode the partition_table should have the efuse
partition. partition.csv: "efuse_em, data, efuse, , 0x2000,". During startup, the eFuses are copied
from flash or, in case if flash is empty, from real eFuse to RAM and then update flash. This option allows keeping
eFuses after reboots (possible to test secure_boot and flash_encryption features with this option).
espefuse.py esptool includes a useful tool for reading/writing ESP32-S2 eFuse bits - espefuse.py.
espefuse.py -p PORT summary
Connecting....
Detecting chip type... ESP32-S2
espefuse.py v3.1-dev
EFUSE_NAME (Block) Description = [Meaningful␣
,→Value] [Readable/Writeable] (Hex Value)
--------------------------------------------------------------------------
,→--------------
Calibration fuses:
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Espressif Systems 810
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