6.3 Nonvolatile Memory (eFuse)

The ATWILC1000-MR110xB modules have 768 bits of nonvolatile eFuse memory that is read by the CPU after device reset. The eFuse is partitioned into six 128-bit banks (Bank 0 – Bank 5). Each bank has the same bit map (see the following figure). The purpose of the first 108 bits in each bank is fixed and the remaining 20 bits are general-purpose, software-dependent bits or reserved for future use.

Note: If IQ Amp Used, IQ Amp Correction, IQ Pha Used and IQ Pha Correction bit fields are programmed, Bank 2 must not be programmed with any values, and only the Bank Invalid bit must be programmed.

This nonvolatile one-time-programmable (OTP) memory can be used for storing the following customer-specific parameters:

MAC address
Calibration information (crystal frequency offset and so on)
Other software-specific configuration parameters

Each bank can be programmed independently, which allows for several updates of the device parameters following the initial programming. For example, if the MAC address is currently programmed in Bank 1, and to update the new MAC address, perform the following steps:

Invalidate the contents of Bank 1 by programming the Bank Invalid bit field of Bank 1.
If the IQ Amp Used, IQ Amp Correction, IQ Pha Used, and IQ Pha Correction bit fields are programmed, skip Bank 2 by programming only the Bank Invalid bit of Bank 2 (see above note).
Program Bank 3 with the new MAC address along with the values of ADC Calib (if used in Bank 1), Frequency Offset (from Bank 1), IQ Amp Correction (from Bank 1) and IQ Pha Correction (from Bank 1). The Used bit field for each corresponding value bit field should also be programmed.
Validate the contents of Bank 3 by programming the Bank Used bit field of Bank 3.

Each bit field (i.e., MAC Address, ADC Calibration, Frequency Offset, IQ Amp Correction, and IQ Pha Correction) has its corresponding Used bit field. Each Used bit field indicates the firmware that the value in the related bit field is valid. A value of '0' in the Used bit field indicates that the following bit field is invalid and a value of '1' programmed to the Used bit field indicates that the corresponding bit field is valid and can be used by firmware. By default, ATWILC1000-MR110xB modules are programmed with the MAC Address, Frequency Offset, IQ Amp, and IQ Phase fields of Bank 1.

Figure 6-1. Bit Map for ATWILC1000-MR110xB eFuse Bank

Note: The bit map has been updated with the IQ Amp Correction and IQ Pha Correction fields from firmware version 15.3 for WILC Linux, and 4.5 for WILC RTOS onwards. Earlier these bit fields were reserved for future use. For customers using a firmware older than 15.3 for WILC Linux and 4.5 for WILC RTOS, the IQ Amp Correction and IQ Pha Correction bit fields must not be used by the firmware. The matrix table below provides details on how different versions of the firmware handle the IQ Amp Used, IQ Amp Correction, IQ Pha Used, and IQ Pha Correction bit fields during Initialization.


Firmware Version	IQ Amp Used and IQ Pha Used Bit Status
Firmware Version	Device with IQ Amp Used and IQ Pha Used Bit Fields with Value as ‘`1`’	Device with IQ Amp Used and IQ Pha Used Bit Fields with Value as ‘`0`’
15.3 or later for WILC Linux 4.5 or later for WILC RTOS	The firmware loads the IQ calibration values from the IQ Amp Correction and IQ Pha Correction bit fields of the corresponding eFuse bank and proceeds with Initialization.	The firmware ignores the values in the IQ Amp Correction and IQ Pha Correction bit fields and proceeds with Initialization.
Prior to 15.3 for WILC Linux Prior to 4.5 for WILC RTOS	The firmware does not check for the IQ Amp Used and IQ Pha Used bit fields and proceeds with Initialization.