4.3 Nonvolatile Memory (eFuse)

The ATWINC15x0-MR210xB modules have 768 bits of nonvolatile eFuse memory that can be 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 0 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 2 and to update the new MAC address, perform the following steps:
  1. Invalidate the contents of Bank 2 by programming the Bank Invalid bit field of Bank 2.
  2. Program Bank 3 with the new MAC address along with the values of ADC Calib (if used in Bank 2), Frequency Offset (from Bank 2), IQ Amp Correction (from Bank 2) and IQ Pha Correction (from Bank 2). The Used bit field for each corresponding value bit field should also be programmed.
  3. 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, ATWINC15x0-MR210xB modules are programmed with the MAC address, Frequency Offset bits, IQ Amp and IQ Phase fields of Bank 2.

Figure 4-1. Bit map for ATWINC15x0-MR210xB eFuse Bank
Note: The bit map has been updated with the IQ Amp correction and IQ Pha Correction fields from firmware version 19.7 onwards. Earlier these bit fields were reserved for future use. For customers using firmware older than 19.7, IQ Amp correction and IQ Pha Correction bit fields are not used by the firmware.

The matrix table below provides details on how different versions of the firmware would handle the IQ Amp used, IQ Amp correction, IQ Pha used and IQ Pha correction bit fields during Initialization.

Firmware Version Used by CustomerIQ Amp Used and IQ Pha Used Bit Status
Device with IQ Amp Used and IQ Pha Used Bits with Value ‘1’Device with IQ Amp Used and IQ Pha Used Bits with Value ‘0’
19.7 or later for ATWINC15x0Firmware loads the IQ cal values from the IQ Amp correction and IQ Pha correction bit fields of corresponding eFuse bank and proceeds with Initialization.Firmware ignores the values in the IQ Amp correction and IQ pha correction bit fields of corresponding eFuse bank and proceeds with initialization.
Prior to 19.7 for ATWINC15x0Firmware does not check for the IQ Amp and IQ Pha used bit fields and proceeds with Initialization.