On my blog I’ve already posted about the development board Wemos designed for the esp32 chip and that, on many webstores, you can find boards that “copy” the Lolin32 name but are instead clones of other opensource projects.
Few weeks ago Wemos published on its official site and make available on its store on Aliexpress a new revision of the board, now named Lolin32 LITE. Thanks to my friend Mauro Alfieri I was able to test a copy:
The main features of the board are the same as the old one:
- esp32 chip
- PH-2 (2mm) connector for a LiPo 1S battery
- charging circuit via USB (max 500mA)
At a visual comparison it is immediately noticeable that the LITE is slightly smaller than the previous, being 5mm long compared to the 5.8mm of the Lolin32:
The smaller length forced Wemos to reduce the number of available pins (19 instead of 26) and to abandon the use of the ESP-WROOM-32 module soldering the esp32 chip and flash memory directly onto the PCB, which also accomodates the antenna.
Speaking of components, for the LITE version Wemos decided to change the chip used to perform the USB-serial conversion and adopted the CH340G IC (which I also used in this project). Finally, the card in my possession uses the latest revision of the esp32 chip (labeled 302017):
esp32, chip revisions
In the same way that software programs have bugs, even hardware chips may have problems due to errors in their design. Producers resolve these errors by producing a new chip revision and keeping updated a document with the known bugs for the different revisions and the possible workarounds.
Espressif manufactured two different revisions of the esp32 chip to date:
If you want to know the revision of a chip, you can use the espefuse.py utility included in the esptool package:
specify the serial port (-p) your board is connected to and the summary command.
Observing the values of CHIP_VERSION and CHIP_PACKAGE you can determine the revision of the chip, for example my Lolin32 board has a chip with revision 0:
while the new Lolin32 LITE a chip with revision 1: