Module Silk Marking
Espressif module silk marking provides information such as module name, flash size, and operating temperature.
Marking Convention

Module Silk Marking Diagram
Company Logo: ESPRESSIF logo.
Module Name: Espressif module name.
Certification ID: Indicates the certification this module has passed.
Company Name: Espressif Systems (Shanghai) Co., Ltd (in Chinese).
Specification Identifier: See Specification Identifier Convention below.
Data Matrix: See Data Matrix Convention below.
Specification Identifier Convention
The Specification Identifier is defined by Espressif to indicate the product status, operating temperature, and the memory inside Espressif modules.

Module Specification Identifier Diagram
- Product Status (2 characters):
XX or MN: mass production
Others: NPI product
See details in the Note below.
- Temperature (1 character):
N: 85 °C/65 °C
H: 105 °C
- Flash Size (1 character or 2 characters):
2: 2 MB
4: 4 MB
8: 8 MB
16: 16 MB
32: 32 MB
- PSRAM (1 character):
R: PSRAM inside
- PSRAM Size (1 character):
2: 2 MB
8: 8 MB
- Reserved:
2 characters: for customized product
0 character: mass production product
Note
- Product Status:
XX is used for products launched earlier;
MN is commonly used for newly launched products or products with new chip revisions launched. For example, M0, M1 or MA, MB….
Examples of other possible codes can be E1, D2, and P3, indicating this is an NPI product under development or in trail run.
Note
- The PSRAM and PSRAM Size fields only exist if this module comes with PSRAM. For example,
XXN4: indicates the module comes with 4 MB flash and no PSRAM.
XXN4R2: indicates the module comes with 4 MB flash and 2 MB PSRAM.
Data Matrix Convention
Scanning the Data Matrix on Espressif modules returns you an 18-character code. The convention for this code is described below:
Character (from left to right) |
Description |
---|---|
Character 1 and Character 2 |
Reserved for Espressif use |
Character 3 to Character 6 |
The production Date Code (YYWW), indicating the WW week of YYYY year |
Character 7 to Character 18 |
Module MAC ID |